Improve "GDK_ROOT not found" message

Closes https://gitlab.com/gitlab-org/gitlab-development-kit/issues/168

See merge request !213

Document how to recompile gitlab-workhorse in GDK

When you run `make` in gitlab-workhorse in GDK you compile new
binaries but those do not get picked up by `gdk run`. You have to use
`gdk install` instead.

See merge request !212

Add psql, redis-cli subcommands

This makes it easier to connect to the Postgres, Redis databases spawned by `gdk run db`.

See merge request !211

Use $host for slapd

See merge request !208

Add `npm install` to `gdk update`

Update the `gitlab-update` rule with an `npm install` system command.

See merge request !207

added .gitlab-npm to touch target during setup

Refuse to run if the GDK root was moved

This is a cause of problems for users. Although we already made fixing
it easy (gdk reconfigure) it was still hard for users to detect /
understand what was wrong.

See merge request !209

This is a cause of problems for users. Although we already made fixing
it easy (gdk reconfigure) it was still hard for users to detect /
understand what was wrong.

Document setting up GitLab Runner against a GDK-supervised GitLab

Closes #144

See merge request !177

Adding OSX macports installation instructions



See merge request !204

* adjustments based  on Jacob's comments

Change readme steps from bullet to numbered list

Since the line before the steps mention the number of steps, I think it would be better to change the bullet list to a numbered list

See merge request !201

Add FreeBSD to prepare.md

Add FreeBSD install instructions to prepare.md and improve pre-requisites section.

See merge request !196

Ignore local gemset configuration

Why? For the case you have different gemsets for different development areas (to avoid gem collisions etc)

See merge request !202

Link to rbenv/chruby

Similar to 4a5099c5

See merge request !203

improves mysql installation doc

The information presented in the doc was not correct this MR aims to fix that

See merge request !198

Similar to 4a5099c5

I think it's critical to note that it may not be obvious for every user that eve…

I think it's critical to note that it may not be obvious for every user that ever choses to use vagrant with docker, that when the multiple prompts to enter the password upon "vagrant run" i.e when Resyncing folders, appear, they are actually all for different operations, so some users may think that they are actually key'ing in the wrong password.

See merge request !200

I think it's critical to note that it may not be obvious for every user that ever choses to use vagrant with docker, that when the multiple prompts to enter the password upon "vagrant run" i.e when resyncing folders, appear, they are actually all for different operations, so some users may think that they are actually key'ing in the wrong password.

Corrected typo in section title

Letters in "from" were inadvertently transposed as "form"

See merge request !199

RFC: bsd-compatible makefile

The "shell" function -- $(shell cmd), to execute cmd in the shell -- is a GNU extensions. There are two options: one of them is to use the grave accent, as in this proposed change; the other is to use the shell assignment operator "!=", originally found in BSDs and implemented by GNU make later.

See merge request !197