SchemaPlus is a gem that simply pulls in a collection of other gems from the SchemaPlus family of ActiveRecord extensions

In an ActiveRecord migration, set the default to create a foreign key and index for all columns that define relatoins.

SchemaAssociations extends ActiveRecord to automatically create associations by inspecting the database schema. This is more more DRY than the standard behavior, for which in addition to specifying the foreign key in the migration, you must also specify complementary associations in two model files (e.g. a :belongs_to and a :has_many).

Adds support for multiple schemas in activerecord when using Postgres

Ever found yourself wanting a modest amount of fresh rows from a production database for development purposes, but put back by the need to maintain referential integrity in the extracted data sample? This data sampler utility will take care that referential dependencies are fulfilled by recursively fetching any rows referred to by the sample.