pg_index_where will provide unique index with WHERE statement on PostgreSQL with migrate the database on Rails.

pg_jbuilder is a tool to dump database queries directly to a JSON object or array. It uses PostgreSQL's JSON functions ([array_to_json and row_to_json](http://www.postgresql.org/docs/9.3/static/functions-json.html)) to serialize the JSON completely bypassing ActiveRecord/Arel. This gives a large speed boost compared to serializing the JSON inside of Ruby/Rails. It is perfect for creating JSON APIs with very low response times.

A gem to facilitate the use of LIKE ANY and LIKE ALL PostgreSQL operators with Rails ActiveRecord

Simple manager for PostgreSQL objects like triggers and functions

ActiveRecord::Migration utility for creating partitions in PostgreSQL.

Disable load balancing by Pgpool-II for Rails apps.

Easily use randomized keys instead of sequential values for your record surrogate ids.

ActiveRecord PostgreSQL auto-reconnection, works with 2.3 and 3.2 rails.

Simple ActiveRecord PostgreSQL full text backed by Arel

serializes rails models from postgres (9.5+)

pg_space_cadet is a simple hack for postgreSQL and ActiveRecord which provides a uuids table of distributable identities of space cadets -- ActiveRecord::Base instances which use the SpaceCadetWrapper. Each space cadet has a default ActiveRecord id unique in the set of all local space cadets; a space cadet's id is derived from its uuid - UUID's are by design universally distributable.

Postgresql Sql Caller for ActiveRecord.

A gem that makes working with tags stored in a Postgresql column easy. Support for array of string, integer and jsonb values.

Retries database transaction on deadlock and transaction serialization errors.

Trigram similarity, guaranteed equivalent to postgres's. Oh yeah.

Manage PostgreSQL custom types (composite types, enums, domains) in your Rails application with versioned migrations and schema handling. This cuts the need for keeping a structure.sql while still maintaining proper type definitions in your Rails application.

PostgreSQL notifications with persistence.

Active Record (>=3.0) plugin which allows you to hide and restore records without actually deleting them. Check its GitHub page for more in-depth information.

Phil_columns adapter for activerecord. See README for more details.

Gem for easy log rotation and S3 upload