Merge branch 'doc_styleguide' into 'master'

Move doc_styleguide in the development directory

Reference #3841 

And also add many new styleguides:

- Naming
- Images
- Links
- Headings
- Formatting
- Notes
- API

See merge request !2386

CONTRIBUTING.md

@@ -334,9 +334,9 @@ merge request:
 1.  [CoffeeScript](https://github.com/thoughtbot/guides/tree/master/style/coffeescript)
 1.  [Shell commands](doc/development/shell_commands.md) created by GitLab
     contributors to enhance security
-1.  [Markdown](http://www.cirosantilli.com/markdown-styleguide)
 1.  [Database Migrations](doc/development/migration_style_guide.md)
-1.  [Documentation styleguide](doc_styleguide.md)
+1.  [Markdown](http://www.cirosantilli.com/markdown-styleguide)
+1.  [Documentation styleguide](doc/development/doc_styleguide.md)
 1.  Interface text should be written subjectively instead of objectively. It
     should be the GitLab core team addressing a person. It should be written in
     present time and never use past tense (has been/was). For example instead

doc/README.md

@@ -70,6 +70,8 @@
 ## Contributor documentation
+- [Documentation styleguide](development/doc_styleguide.md) Use this styleguide if you are
+  contributing to documentation.
 - [Development](development/README.md) Explains the architecture and the guidelines for shell commands.
 - [Legal](legal/README.md) Contributor license agreements.
 - [Release](release/README.md) How to make the monthly and security releases.

doc/development/doc_styleguide.md

+# Documentation styleguide
+
+This styleguide recommends best practices to improve documentation and to keep
+it organized and easy to find.
+
+## Naming
+
+- When creating a new document and it has more than one word in its name,
+  make sure to use underscores instead of spaces or dashes (`-`). For example,
+  a proper naming would be `import_projects_from_github.md`. The same rule
+  applies to images.
+
+## Text
+
+- Split up long lines, this makes it much easier to review and edit. Only
+  double line breaks are shown as a full line break in [GitLab markdown][gfm].
+  80-100 characters is a good line length
+- Make sure that the documentation is added in the correct directory and that
+  there's a link to it somewhere useful
+- Do not duplicate information
+- Be brief and clear
+- Unless there's a logical reason not to, add documents in alphabetical order
+- Write in US English
+- Use [single spaces][] instead of double spaces
+
+## Formatting
+
+- Use dashes (`-`) for unordered lists instead of asterisks (`*`)
+- Use the number one (`1`) for ordered lists
+- Use underscores (`_`) to mark a word or text in italics
+- Use double asterisks (`**`) to mark a word or text in bold
+- When using lists, prefer not to end each item with a period. You can use
+  them if there are multiple sentences, just keep the last sentence without
+  a period
+
+## Headings
+
+- Add only one H1 title in each document, by adding `#` at the beginning of
+  it (when using markdown). For subheadings, use `##`, `###` and so on
+- Avoid putting numbers in headings. Numbers shift, hence documentation anchor
+  links shift too, which eventually leads to dead links. If you think it is
+  compelling to add numbers in headings, make sure to at least discuss it with
+  someone in the Merge Request
+- When introducing a new document, be careful for the headings to be
+  grammatically and syntactically correct. It is advised to mention one or all
+  of the following GitLab members for a review: `@axil`, `@rspeicher`,
+  `@dblessing`, `@ashleys`, `@nearlythere`. This is to ensure that no document
+  with wrong heading is going live without an audit, thus preventing dead links
+  and redirection issues when corrected
+- Leave exactly one newline after a heading
+
+## Links
+
+- If a link makes the paragraph to span across multiple lines, do not use
+  the regular Markdown approach: `[Text](https://example.com)`. Instead use
+  `[Text][identifier]` and at the very bottom of the document add:
+  `[identifier]: https://example.com`. This is another way to create Markdown
+  links which keeps the document clear and concise. Bonus points if you also
+  add an alternative text: `[identifier]: https://example.com "Alternative text"`
+  that appears when hovering your mouse on a link
+
+## Images
+
+- Place images in a separate directory named `img/` in the same directory where
+  the `.md` document that you're working on is located. Always prepend their
+  names with the name of the document that they will be included in. For
+  example, if there is a document called `twitter.md`, then a valid image name
+  could be `twitter_login_screen.png`.
+- Images should have a specific, non-generic name that will differentiate them.
+- Keep all file names in lower case.
+- Consider using PNG images instead of JPEG.
+
+Inside the document:
+
+- The Markdown way of using an image inside a document is:
+  `![Proper description what the image is about](img/document_image_title.png)`
+- Always use a proper description for what the image is about. That way, when a
+  browser fails to show the image, this text will be used as an alternative
+  description
+- If there are consecutive images with little text between them, always add
+  three dashes (`---`) between the image and the text to create a horizontal
+  line for better clarity
+- If a heading is placed right after an image, always add three dashes (`---`)
+  between the image and the heading
+
+## Notes
+
+- Notes should be in italics with the word `Note:` being bold. Use this form:
+  `_**Note:** This is something to note._`. If the note spans across multiple
+  lines it's OK to split the line.
+
+## New features
+
+- Every piece of documentation that comes with a new feature should declare the
+  GitLab version that feature got introduced. Right below the heading add a
+  note: `_**Note:** This feature was introduced in GitLab 8.3_`
+- If possible every feature should have a link to the MR that introduced it.
+  The above note would be then transformed to:
+  `_**Note:** This feature was [introduced][ce-1242] in GitLab 8.3_`, where
+  the [link identifier](#links) is named after the repository (CE) and the MR
+  number
+- If the feature is only in GitLab EE, don't forget to mention it, like:
+  `_**Note:** This feature was introduced in GitLab EE 8.3_`. Otherwise, leave
+  this mention out
+
+## API
+
+Here is a list of must-have items. Use them in the exact order that appears
+on this document. Further explanation is given below.
+
+- Every method must have the REST API request. For example:
+
+    ```
+    GET /projects/:id/repository/branches
+    ```
+
+- Every method must have a detailed
+  [description of the parameters](#method-description).
+- Every method must have a cURL example.
+- Every method must have a response body (in JSON format).
+
+### Method description
+
+Use the following table headers to describe the methods. Attributes should
+always be in code blocks using backticks (`).
+
+```
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+```
+
+Rendered example:
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `user`  | string | yes | The GitLab username |
+
+### cURL commands
+
+- Use `https://gitlab.example.com/api/v3/` as an endpoint.
+- Wherever needed use this private token: `9koXpg98eAheJpvBs5tK`.
+- Always put the request first. `GET` is the default so you don't have to
+  include it.
+- Use double quotes to the URL when it includes additional parameters.
+- Prefer to use examples using the private token and don't pass data of
+  username and password.
+
+| Methods | Description |
+| ------- | ----------- |
+| `-H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK"` | Use this method as is, whenever authentication needed |
+| `-X POST`   | Use this method when creating new objects |
+| `-X PUT`    | Use this method when updating existing objects |
+| `-X DELETE` | Use this method when removing existing objects |
+
+### cURL Examples
+
+Below is a set of [cURL][] examples that you can use in the API documentation.
+
+#### Simple cURL command
+
+Get the details of a group:
+
+```bash
+curl -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/groups/gitlab-org
+```
+
+#### cURL example with parameters passed in the URL
+
+Create a new project under the authenticated user's namespace:
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects?name=foo"
+```
+
+#### Post data using cURL's --data
+
+Instead of using `-X POST` and appending the parameters to the URI, you can use
+cURL's `--data` option. The example below will create a new project `foo` under
+the authenticated user's namespace.
+
+```bash
+curl --data "name=foo" -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects"
+```
+
+#### Post data using JSON content
+
+_**Note:** In this example we create a new group. Watch carefully the single
+and double quotes._
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" -H "Content-Type: application/json" --data '{"path": "my-group", "name": "My group"}' https://gitlab.example.com/api/v3/groups
+```
+
+#### Post data using form-data
+
+Instead of using JSON or urlencode you can use multipart/form-data which
+properly handles data encoding:
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" -F "title=ssh-key" -F "key=ssh-rsa AAAAB3NzaC1yc2EA..." https://gitlab.example.com/api/v3/users/25/keys
+```
+
+The above example is run by and administrator and will add an SSH public key
+titled ssh-key to user's account which has an id of 25.
+
+#### Escape special characters
+
+Spaces or slashes (`/`) may sometimes result to errors, thus it is recommended
+to escape them when possible. In the example below we create a new issue which
+contains spaces in its title. Observe how spaces are escaped using the `%20`
+ASCII code.
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/projects/42/issues?title=Hello%20Dude"
+```
+
+Use `%2F` for slashes (`/`).
+
+#### Pass arrays to API calls
+
+The GitLab API sometimes accepts arrays of strings or integers. For example, to
+restrict the sign-up e-mail domains of a GitLab instance to `*.example.com` and
+`example.net`, you would do something like this:
+
+```bash
+curl -X PUT -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" -d "restricted_signup_domains[]=*.example.com" -d "restricted_signup_domains[]=example.net" https://gitlab.example.com/api/v3/application/settings
+```
+
+[cURL]: http://curl.haxx.se/ "cURL website"
+[single spaces]: http://www.slate.com/articles/technology/technology/2011/01/space_invaders.html
+[gfm]: http://doc.gitlab.com/ce/markdown/markdown.html#newlines "GitLab flavored markdown documentation"

doc_styleguide.md

 # Documentation styleguide
-This styleguide recommends best practices to improve documentation and to keep it organized and easy to find. 
-
-## Text
-
-- Split up long lines, this makes it much easier to review and edit. Only
-double line breaks are shown as a full line break in markdown. 80 characters
-is a good line length.
-- For subtitles, make sure to start with the largest and go down, meaning:
-`#` for the title, `##` for subtitles and `###` for subtitles of the subtitles, etc.
-- Make sure that the documentation is added in the correct directory and that there's a link to it somewhere useful.
-- Add only one H1 or title in each document, by adding '#' at the begining of it (when using markdown). 
-For subtitles, use '##', '###' and so on.
-- Do not duplicate information.
-- Be brief and clear.
-- Whenever it applies, add documents in alphabetical order.
-- Write in US English
-- Use [single spaces](http://www.slate.com/articles/technology/technology/2011/01/space_invaders.html) instead of double spaces.
-
-## Images
-
-- Create a directory to store the images with the specific name of the document where the images belong. 
-It could be in the same directory where the .md document that you're working on is located.
-- Images should have a specific, non-generic name that will differentiate them.
-- Keep all file names in lower case.
\ No newline at end of file
+Moved to [development/doc_styleguide](doc/development/doc_styleguide.md).