Added description for Redis connection via unix socket

Now when you want to signup or change existing email you will be forced
to confirm that you really own this email. You get email with link to
follow in order to confirm your email address

Conflicts:
	app/models/user.rb

Improve the repository import message

Fix the sigil for merge request emails

Ex. redirect from
  localhost/group/project.git
to
  localhost/group/project

It used to prevent 404 error when follow submodule http link
like http://localhost/group/project.git

This reverts commit 20c47923.