A friend of mine was over tonight and we were troubleshooting a issue with SVN authentication via the Redmine project management software. Redmine is built with Ruby and on this server is running via Apache and Mongrel. I needed to set the project to run in development mode but wasn’t very familiar with the Mongrel setup. After some research I found it was easy to change the environment from production to development using the Mongrel Cluster .yml file for that project. When using Mongrel each site appears to get its own .yml file so you can modify whatever settings you want to on a per site basis. Below I describe what needs to be changed, default locations, and any other actions that need to be taken to restart the Ruby on Rails project in development mode.