Squasher is a compressor of the old migrations in a rails application. If you works on the big project with lots of migrations every rake db:migrate takes a few seconds, creating of a new database might takes a few minutes. It's just because rails loads all this files. Squasher instead removes all this migrations and creates a single migration with a final database state of the specified date(a new migration will look like a schema).

You should not add this to Gemfile. Just standalone installation:

$ gem install squasher

@Note if you use Rbenv don't forget to run rbenv rehash.

Suppose your application was created a few years ago. %app_root%/db/migrate folder is like below list:

2009...._first_migration.rb
2009...._another_migration.rb
# and a lot of other files
2011...._adding_model_foo.rb
# few years later
2013...._removing_model_foo.rb
# and so one

Storing this atomic changes with time is more painful and useles. It's time to archive all this stuff. Once you install gem you will get squasher command.

$ squasher 2014 #compress all migrations which were created prior to 2014 year

You can tell squasher a more detailed date, for example:

$ squasher 2013/12    #prior December 2013
$ squasher 2013/12/19 #prior 19 December 2013

It works and was tested on Ruby 1.9.3+ and Rails 3.1+. Also it requires a valid configuration in config/database.yml and using Ruby format in db/schema.rb(default rails use-case). If a some migration insert data(create a ActiveRecord model records) you will lost this code in a new created migration, BUT squasher will ask you to leave a tmp database which will have all inserted information. Using this database you could again add this inserting into a new migration or create/update config/seed.rb file(expected place for this stuff).

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request