Fixed a nginx configuration

For some reason, if the nginx configuration is bound to an IP, it breaks the install, causing all git clone/push/pull operations to die with a 'fatal: The remote end hung up unexpectedly' message. Changing this configuration seems to fix the problem. I reckon that this is just a temporary fix. I don't know the ins and outs of GitLab well enough to vouch for this change, but I do know that these instructions are broken, and that this update will fix them.
Configure git global settings

Setting Git's global user.name and user.email are missing from
instructions, causing check.rake to fail at this step.

Signed-off-by: Axilleas Pipinellis <axilleas@archlinux.gr>
Migrate notes.line_code format.

Since version 4.1, notes.line_code means:
  {SHA1 hash of file path}_{old line}_{new line}
but the older version means:
  {file index of the commit}_{old line}_{new line}

This rake task migrate the above differences.
fixed capitalization and added Google Analytics
System calls were using unsanitized user input
fixed fact about memory usage
update links to be relative paths and add CONTRIBUTING.md link
More strict validation for SSH Key content
Merge pull request #3911 from babatakao/migrate_note_linecode

Migrate notes.line_code format.
Merge pull request #3918 from joeandaverde/unsanitized

System calls to gitlab-shell were using unsanitized user input
Merge pull request #3894 from axilleas/gitconfig-fix

Configure git global settings in installation docs
Merge pull request #3912 from bbodenmiller/patch-6

fixed capitalization and added Google Analytics
Merge pull request #3920 from bbodenmiller/patch-7

fixed fact about memory usage
Merge pull request #3921 from bbodenmiller/patch-8

update links to be relative paths and add CONTRIBUTING.md link
Merge pull request #3863 from crazyscience/patch-4

Fixed a nginx configuration