Since mysql doesn’t support transactional table modifications (i.e. you can’t wrap ALTER in BEGIN/COMMIT) every so often you’ll get migrations that fail, putting your database in schema purgatory.
A handy way to deal with this is to run migrations manually from console like this:
ActiveRecord::Migration.add_index :commonalities, :match_id
ActiveRecord::Migration.remove_column :users, :middle_name
Of course, these will run against whatever environment you started console with.
