Easy access and creation of "has many" relationships for ActiveRecord models. It uses a "vertical table" so schema changes aren't necessary when you add fields. Use this plugin to add preferences, options, flags, etc to your models

Put EAV behaviour on your ActiveRecord models

Gem for and Rails3 to easily handle enumeration attributes in ActiveRecord's models

Simple heartbeat monitoring target for Rails apps with database connection testing, customizable output, HTTP status code, and Airbrake notification.

Store ActiveRecord IDs non-obviously in URL using hashids.

Automatic strong parameter detection with Hashie and Rails 4.

Allow addition of custom 'magic' columns to ActiveRecord models.

Custom fields forActiveRecord models, suppport Rails 4!

Simple replacement for has_many_polymorphs

Keep specified associations in sync with ease using async reindexing (searchkick gem is required).

Bind a remote ActiveResource object to your local ActiveRecord objects, delegate attributes and optionally cache remote attributes locally.

vCard like contact and address models and helpers for Rails.

Take rails constants' loading under control

Helena is an online survey/test framework designed for agile survey/test development, longitudinal studies and instant feedback.

Ruby library for image galleries generation.

heroku_external_db lets you specify multiple databases using Heroku-style DATABASE_URL parameters, wire them up to different ActiveRecord configurations, and automatically configure it from the Rails environment. It also adds support for the :sslca configuration parameter so you can talk to external MySQL servers over SSL.

A Rails engine for in-app notifications.

Adds ActiveRecord support for hierarchical data structures using PostgreSQL's LTREE column type.

Rails pipeline wraper for highlight.js

This adds a lab interface to the OpenMRS compatible core API provided by [HIS-EMR-API](https://github.com/EGPAFMalawiHIS/HIS-EMR-API).