fix build failure

(https://travis-ci.org/gitlabhq/gitlabhq/builds/3593153)
Show only ≤16 lines of code in a discussion (fix issue #2860).
A little bit of codestyle improvments
System hooks execution moved to System hook service
Method moved to service
Migrations for convertion merge_status added
Database schema updated
State machine added for merge_status field
class.self methods moved to scopes
human_merge_status replaced by human_merge_status_name
We don't need to check .profile now that gitolite is replaced by gitlab-shell
An Id must be sended to queue
Distorted lines in `diff`

Distorted lines in `diff` when viewing files `windows-style-line-separator: \r\n`
Update grit for ruby 2.0 support
Update grit to handle symlinks
Merge pull request #3057 from axilleas/master

Remove function 'check_issue_1059_shell_profile_error' from check.rake as it is not needed anymore
Merge pull request #3052 from Undev/system-hook-observer-improves

System hooks code & logic refactoring
Move git post push logic to service
correct indentation in activity observer
Remove gitolite mention from docs