Update markdown reference to external issues

1. Issue may be not only in jira.
2. Rewrite method for support different external issue trackers
Delete mailer queue because we don't use sidekiq_mailer gem and now the mailer queue doesn't exist any more.
change bash to sh
fix bash-ism
don't lookup branch element - it might need to be escaped
Update user_management.md

add rails_env to commands
Update markdown.rb

Fix mistake by @qqshfox report
move env to end of lines
fix link_to by @bwrsandman

Add missing '#'
add current sign-in date

add current sign-in date to admin section profile view
add missing config files to check during release process
Adding in snippet search functionality

http://feedback.gitlab.com/forums/176466-general/suggestions/5529795-search-though-snippets
Fine-tune the Remove Project redirect. Now it redirects to admin_projects_path and shows a flash message confirming the action has been taken.
change git to git bin path
Add permalink to fixed SHA URL on blob view.
Add tests for finding an oauth authenticated user
Use local vars for tests
Add users with predictable username and password

to development seed.
Handle user creation if email is not provided

This fixes #1541
Ensure oath callbacks without a nickname work (google)