Migrating an old database with old migrations can be a pain because the migrations often depend on code that doesn't exist in the latest version of the application. The simplest solution is to checkout to the commit where each migration was introduced (or last modified) and run each migration from there, but this can be time-consuming and tedious. Farfugl automates this process.
You can install Farfugl on your system like any other gem:
gem install farfugl
You can also add gem 'farfugl' to your Rails application's Gemfile and run
bundle.
Please note that Farfugl is still under development and may not be completely stable; always create backups of your database before using it.
Running Farfugl is simple:
rake farfugl:migrate