Pundit - Pundit provides a set of helpers which guide you in leveraging regular Ruby classes and object oriented design patterns to build a simple, robust and scaleable authorization system.

cancancan - Continuation of CanCan, the authorization Gem for Ruby on Rails.CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the Ability class) and not duplicated across controllers, views, and database queries.

rolify - Role management library with resource scoping.

acl9 - Acl9 is a role-based authorization system that provides a concise DSL for securing your Rails application.

Omniauth

omniauth-facebook

omniauth-google-oauth2

omniauth-weibo-oauth2

omniauth-twitter

omniauth-github

omniauth-linkedin-oauth2

Active Record

Enumerize - Enumerated attributes with I18n and ActiveRecord/Mongoid support. It can be integrated with Simple Form.

counter_culture - Turbo-charged counter caches for your Rails app. Huge improvements over the Rails standard counter caches.

custom_counter_cache - A simple approach to creating a custom counter cache that can be used across multiple models.

Sequenced - Sequenced is a simple gem that generates scoped sequential IDs for ActiveRecord models.

FriendlyId - FriendlyId is the “Swiss Army bulldozer” of slugging and permalink plugins for ActiveRecord. It allows you to create pretty URL’s and work with human-friendly strings as if they were numeric ids for ActiveRecord models.

AASM - State machines for Ruby classes (plain Ruby, Rails Active Record, Mongoid).

PaperTrail - PaperTrail lets you track changes to your models' data. It's good for auditing or versioning.

paranoia - ActiveRecord plugin allowing you to hide and restore records without actually deleting them.

Validates - Validates provides collection of useful custom validators for Rails applications, including:

EmailValidator

UrlValidator

SlugValidator

MoneyValidator

IpValidator

AssociationLengthValidator

AbsolutePathValidator

UriComponentValidator

ColorValidator

EanValidator (EAN-8 & EAN-13)

globalize - Rails I18n de-facto standard library for ActiveRecord model/data translation.

deep_cloneable - This gem gives every ActiveRecord::Base object the possibility to do a deep clone that includes user specified associations.

social_shares - Check how many times url was shared in social networks.

public_activity - Easy activity tracking for models - similar to Github's Public Activity.

Awesome Rails Gem

A collection of awesome Ruby Gems for Rails development.

The goal is to help every Rails developer to build an awesome Rails product/service.

Rails Gem List
User
Active Record
Plugins
API
Email
File Uploading
Searching
Scheduled/Recurrence Jobs
View Helper
Environment Variables
Admin Panel
Logging
Debug
Coding Style
Testing
Production
Error Logging
Database

User

Authentication

Devise - Devise is a flexible authentication solution for Rails based on Warden.
Knock - Seamless JWT authentication for Rails API.
Clearance - Rails authentication with email & password.
Devise token auth - Token based authentication for Rails JSON APIs.
Sorcery - Magical Authentication for Rails. Supports ActiveRecord, DataMapper, Mongoid and MongoMapper.

Authorization

Pundit - Pundit provides a set of helpers which guide you in leveraging regular Ruby classes and object oriented design patterns to build a simple, robust and scaleable authorization system.
cancancan - Continuation of CanCan, the authorization Gem for Ruby on Rails.CanCan is an authorization library for Ruby on Rails which restricts what resources a given user is allowed to access. All permissions are defined in a single location (the Ability class) and not duplicated across controllers, views, and database queries.
rolify - Role management library with resource scoping.
acl9 - Acl9 is a role-based authorization system that provides a concise DSL for securing your Rails application.

Omniauth

Active Record

Enumerize - Enumerated attributes with I18n and ActiveRecord/Mongoid support. It can be integrated with Simple Form.
counter_culture - Turbo-charged counter caches for your Rails app. Huge improvements over the Rails standard counter caches.
custom_counter_cache - A simple approach to creating a custom counter cache that can be used across multiple models.
Sequenced - Sequenced is a simple gem that generates scoped sequential IDs for ActiveRecord models.
FriendlyId - FriendlyId is the “Swiss Army bulldozer” of slugging and permalink plugins for ActiveRecord. It allows you to create pretty URL’s and work with human-friendly strings as if they were numeric ids for ActiveRecord models.
AASM - State machines for Ruby classes (plain Ruby, Rails Active Record, Mongoid).
PaperTrail - PaperTrail lets you track changes to your models' data. It's good for auditing or versioning.
paranoia - ActiveRecord plugin allowing you to hide and restore records without actually deleting them.
Validates - Validates provides collection of useful custom validators for Rails applications, including:
EmailValidator
UrlValidator
SlugValidator
MoneyValidator
IpValidator
AssociationLengthValidator
AbsolutePathValidator
UriComponentValidator
ColorValidator
EanValidator (EAN-8 & EAN-13)
globalize - Rails I18n de-facto standard library for ActiveRecord model/data translation.
deep_cloneable - This gem gives every ActiveRecord::Base object the possibility to do a deep clone that includes user specified associations.
social_shares - Check how many times url was shared in social networks.
public_activity - Easy activity tracking for models - similar to Github's Public Activity.