I'm in the process of setting up Redmine (version 1.0-stable) on an Ubuntu 8.04 virtual machine. Getting a recent enough gem and rails is less fun than you might imagine, but the big issue I came across was a bug in the database model, which makes MySQL 5.1 (MariaDB 5.1 in my case) barf on installation.
There is a fix, but I am running from a git clone didn't want to download and apply a diff file to that repository. A quick google found what I need: the git cherry-pick command. It allows you to grab a single commit and apply its changes to your branch. In my case:
git cherry-pick a628b0f186cf4d182ce5cee1a497ad42c5246406
Because all commits have a unique label, when 1.0.1 is released and I update my git clone, I won't suffer merge conflicts from this already-applied change. Lovely :-)