I wanted to install Gitlab 5.3 on a fresh Ubuntu 12. The tricky part is you need to have a version of git beyond the local apt version. You also want ruby 1.9.3 and only that version. I used mysql for a database but you could use postgres. These are my notes from doing it.
Install git from source (option 2) by following
https://www.digitalocean.com/community/articles/how-to-install-git-on-ubuntu-12-04
This matters because gitlab will check which version of git you are using at the VERY end.
sudo apt-get install ruby1.9.1 ruby1.9.1-dev sudo apt-get install mysql-server sudo apt-get install libmysqlclient-dev sudo apt-get install redis-server sudo apt-get install libxslt-dev libxml2-dev sudo apt-get install libicu-dev sudo gem install nokogiri -v '1.5.9'
Follow the dirctions on https://github.com/gitlabhq/gitlabhq/blob/master/doc/install/installation.md
but make sure to exclude ‘git-core’ in this snippet:
sudo apt-get install -y build-essential zlib1g-dev libyaml-dev libssl-dev libgdbm-dev libreadline-dev libncurses5-dev libffi-dev curl openssh-server redis-server checkinstall libxml2-dev libxslt-dev libcurl4-openssl-dev libicu-dev
This should make a working gitlab server.