Merge branch 'issue-boards-docs-update' into 'master'

Updated issue boards docs

Closes #27872

See merge request !9097

doc/user/project/issue_board.md

 # Issue board
-> [Introduced][ce-5554] in GitLab 8.11.
+>**Notes:**
+- [Introduced][ce-5554] in GitLab 8.11.
+- The Backlog column was replaced by the **Add issues** button in GitLab 8.17.
 The GitLab Issue Board is a software project management tool used to plan,
 organize, and visualize a workflow for a feature or product release.
@@ -28,13 +30,11 @@ Below is a table of the definitions used for GitLab's Issue Board.
 | **List**        | Each label that exists in the issue tracker can have its own dedicated list. Every list is named after the label it is based on and is represented by a column which contains all the issues associated with that label. You can think of a list like the results you get when you filter the issues by a label in your issue tracker. |
 | **Card**        | Every card represents an issue and it is shown under the list for which it has a label. The information you can see on a card consists of the issue number, the issue title, the assignee and the labels associated with it. You can drag cards around from one list to another. Issues inside lists are [ordered by priority](labels.md#prioritize-labels). |
-There are three types of lists, the ones you create based on your labels, and
-two default:
-- **Backlog** (default): shows all issues that do not fall in one of the other lists. Always appears on the very left.
-- **Done** (default): shows all closed issues. Always appears on the very right.
-Label list: a list based on a label. It shows all issues with that label.
+There are two types of lists, the ones you create based on your labels, and
+one default:
 - Label list: a list based on a label. It shows all opened issues with that label.
+- **Done** (default): shows all closed issues. Always appears on the very right.
 ![GitLab Issue Board](img/issue_board.png)
@@ -55,10 +55,10 @@ In short, here's a list of actions you can take in an Issue Board:
 If you are not able to perform one or more of the things above, make sure you
 have the right [permissions](#permissions).
-## First time using the Issue Board
-The first time you navigate to your Issue Board, you will be presented with the
-two default lists (**Backlog** and **Done**) and a welcoming message that gives
+## First time using the issue board
+The first time you navigate to your Issue Board, you will be presented with
+a default list (**Done**) and a welcoming message that gives
 you two options. You can either create a predefined set of labels and create
 their corresponding lists to the Issue Board or opt-out and use your own lists.
@@ -93,23 +93,26 @@ in the list's heading. A confirmation dialog will appear for you to confirm.
 Deleting a list doesn't have any effect in issues and labels, it's just the
 list view that is removed. You can always add it back later if you need.
-## Searching issues in the Backlog list
-The very first time you start using the Issue Board, it is very likely your
-issue tracker is already populated with labels and issues. In that case,
-**Backlog** will have all the issues that don't belong to another list, and
-**Done** will have all the closed ones.
-For performance and visibility reasons, each list shows the first 20 issues
-by default. If you have more than 20, you have to start scrolling down for the
-next 20 issues to appear. This can be cumbersome if your issue tracker hosts
-hundreds of issues, and for that reason it is easier to search for issues to
-move from **Backlog** to another list.
-Start typing in the search bar under the **Backlog** list and the relevant
-issues will appear.
-![Issue Board search Backlog](img/issue_board_search_backlog.png)
+## Adding issues to a list
+
+You can add issues to a list by clicking the **Add issues** button that is
+present in the upper right corner of the issue board. This will open up a modal
+window where you can see all the issues that do not belong to any list.
+
+Select one or more issues by clicking on the cards and then click **Add issues**
+to add them to the selected list. You can limit the issues you want to add to
+the list by filtering by author, assignee, milestone and label.
+![Bulk adding issues to lists](img/issue_boards_add_issues_modal.png)
+## Removing an issue from a list
+Removing an issue from a list can be done by clicking on the issue card and then
+clicking the **Remove from board** button in the sidebar. Under the hood, the
+respective label is removed, and as such it's also removed from the list and the
+board itself.
+![Remove issue from list](img/issue_boards_remove_issue.png)
 ## Filtering issues
@@ -142,8 +145,8 @@ A typical workflow of using the Issue Board would be:
    and gets automatically closed.
 For instance you can create a list based on the label of 'Frontend' and one for
-'Backend'. A designer can start working on an issue by dragging it from
-**Backlog** to 'Frontend'. That way, everyone knows that this issue is now being
+'Backend'. A designer can start working on an issue by adding it to the
+'Frontend' list. That way, everyone knows that this issue is now being
 worked on by the designers. Then, once they're done, all they have to do is
 drag it over to the next list, 'Backend', where a backend developer can
 eventually pick it up. Once they’re done, they move it to **Done**, to close the