Added service redis start

If you don't start the redis server you will get a stacktrace at the end of the tutorial
Update README.md
[Installation script] GitLab 6.x - CentOS 6.x - NGINX

Added a note about the SSL certificate because the nginx config being downloaded is making use of it.
[Installation script] GitLab 6.x - CentOS 6.x - NGINX

Fixed some markup
[Installation script] GitLab 6.x - CentOS 6.x - NGINX

Fixed a typo
Update README.md
reverted the newlines
Merge pull request #124 from Ponsjuh/master

Add note for ssl in nginx, make sure redis is started