Labels are saved in the database with the case they were originally created with.
Before this change if a user created a label with the same text but different case
the label would use the original case and no new label would be created in the
database. With this change, labels are now case-sensitive.

Steps to test:

1. Before this change, create a new issue with a new label "FIxMe"
2. Edit the issue and change the label to "FixMe"
3. Note that the label reverted to "FIxMe"
4. Apply this change
5. Edit the issue again and change the label to "FixMe"
Note that the new case was preserved. If you also look in the database in the "tags" table you will see that both labels are present - "FIxMe" and "FixMe".

 Add check if the signup setting is enabled. fixes #4832

Add hints for relative URL installation

Fixed typo in groups.md

Extended User API to expose admin and can_create_group for user creation...

Changed wording in application.rb and gitlab.yml.example to match unicorn.rb. This is for when using a non-root path

* dont allow protect/unprotect branches for users without master permissions
* dont allow access to Repository api for guests

add rake tasks for web hooks management

Also, is_admin and can_create_group are exposed in the user information.
Fixed attributes_for_keys to process properly keys with boolean values (since false.present? is false).

run mysql_secure_installation to secure the freshly installed mysql server

[gitlab:check] Fix detecting the status of sidekiq

If you are running another sidekiq instance on your server, e.g. GitLab
CI, the check script would parse the output of `ps aux` searching for
`sidekiq` and returning success, although the GitLab sidekiq may not be
running.

Now the `ps` call will only print the processes run by the GitLab user.