SimpleDiscussion - Forum engine for Ruby on Rails

Build Status Gem Version

SimpleDiscussion is a Rails forum gem extracting the GoRails forum. It includes categories, simple moderation, the ability to mark threads as solved, and more.

Out of the box, SimpleDiscussion comes with styling for Bootstrap v4 but you're free to customize the UI as much as you like by installing the views and tweaking the HTML.

GoRails Forum


Before you get started, SimpleDiscussion requires a User model in your application (for now).

Add this line to your application's Gemfile:

gem 'simple_discussion'

And then execute:


Install the migrations and migrate:

rails simple_discussion:install:migrations
rails db:migrate

Add SimpleDiscussion to your User model. The model must have name method which will be used to display the user's name on the forum. Currently only a model named User will work, but this will be fixed shortly.

class User < ActiveRecord::Base
  include SimpleDiscussion::ForumUser

  def name
    "#{first_name} #{last_name}"

Optionally, you can add a moderator flag to the User model to allow users to edit threads and posts they didn't write.

rails g migration AddModeratorToUsers moderator:boolean
rails db:migrate

Add the following line to your config/routes.rb file:

mount SimpleDiscussion::Engine => "/forum"

Lastly, add the CSS to your application.css to load some default styles.

*= require simple_discussion


To get all the basic functionality, the only thing you need to do is add a link to SimpleDiscussion in your navbar.

<%= link_to "Forum", simple_discussion_path %>

This will take the user to the views inside the Rails engine and that's all you have to do!

Customizing All The Things!

If you'd like to customize the views that SimpleDiscussion uses, you can install the views to your Rails app:

rails g simple_discussion:views

You can also install a copy of the SimpleDiscussion controllers for advanced customization:

rails g simple_discussion:controllers

Helpers are available for override as well. They are used for rendering the user avatars, text formatting, and more.

rails g simple_discussion:helpers

NOTE: Keep in mind that the more customization you do, the tougher gem upgrades will be in the future.

Email And Slack Notifications

By default, SimpleDiscussion will attempt to send email and slack notifications for users subscribed to threads. To turn these off you can do the following in config/initializers/simple_discussion.rb

SimpleDiscussion.setup do |config|
  config.send_email_notifications = false # Default: true
  config.send_slack_notifications = false # Default: true

Slack notifications require you to set simple_discussion_slack_url in your config/secrets.yml. If you don't have this value set, it will not attempt Slack notifications even if they are enabled.


After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.


The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the SimpleDiscussion project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.