Schemata is a gem for corralling schema definitions across projects. As we work on new projects a lot of common field requirements come up ( addressess, contact forms, medical forms ) but its rare that the field names are ever implemented the same. Its a minor issue, but a major pet peeve of mine is when 'email_address' is defined as 'email' or 'phone_number' defined as 'phone' (Don't get me started on street_address_1 and all of its relatives ). 

So with schemata you define the fields once and then they are available to use in your migration files.  

gem 'schemata'