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Reputation system Rails engine.
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Merit Gem: Reputation rules (badges, points and rankings) for Rails applications


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  1. Add gem 'merit' to your Gemfile
  2. Run rails g merit:install
  3. Run rails g merit MODEL_NAME (e.g. user)
  4. Depending on your ORM
    • ActiveRecord: Run rake db:migrate
    • Mongoid: Set config.orm = :mongoid in config/initializers/merit.rb
  5. Define badges you will use in config/initializers/merit.rb
  6. Configure reputation rules for your application in app/models/merit/*

NOTE: Mongoid support is experimental.

Defining badge rules

You may give badges to any resource on your application if some condition holds. Badges may have levels, and may be temporary. Define rules on app/models/merit_badge_rules.rb:

grant_on accepts:

  • 'controller#action' string (similar to Rails routes)
  • :badge for badge name
  • :level for badge level
  • :to method name over target_object which obtains object to badge
  • :model_name (string) define controller's name if it differs from the model (like RegistrationsController for User model).
  • :multiple (boolean) badge may be granted multiple times
  • :temporary (boolean) if the receiver had the badge but the condition doesn't hold anymore, remove it. false by default (badges are kept forever).
  • &block
    • empty (always grants)
    • a block which evaluates to boolean (recieves target object as parameter)
    • a block with a hash composed of methods to run on the target object with expected values


grant_on 'comments#vote', :badge => 'relevant-commenter', :to => :user do |comment|
  comment.votes.count == 5

grant_on ['users#create', 'users#update'], :badge => 'autobiographer', :temporary => true do |user| && user.address.present?

Grant manually

You may also grant badges "by hand" (optionally multiple times):

Badge.find(3).grant_to(current_user, :allow_multiple => true)

Defining point rules

Points are a simple integer value which are given to "meritable" resources. They are given on actions-triggered, either to the action user or to the method(s) defined in the :to option. Define rules on app/models/merit_point_rules.rb:


score 10, :to => :post_creator, :on => 'comments#create'

score 20, :on => [

:to method(s) work as in badge rules: they are sent to the target_object. In the following example, after a review gets created both review.reviewer and review.reviewed are granted 15 points:

score 15, :on => 'reviews#create', :to => [:reviewer, :reviewed]

Defining rank rules

5 stars is a common ranking use case. They are not given at specified actions like badges, you should define a cron job to test if ranks are to be granted.

Define rules on app/models/merit_rank_rules.rb:

set_rank accepts:

  • :level ranking level (greater is better)
  • :to model or scope to check if new rankings apply
  • :level_name attribute name (default is empty and results in 'level' attribute, if set it's appended like 'level_#{level_name}')

Check for rules on a rake task executed in background like:

task :cron => :environment do


set_rank :level => 2, :to => do |commiter|
  commiter.branches > 1 && commiter.followers >= 10

set_rank :level => 3, :to => do |commiter|
  commiter.branches > 2 && commiter.followers >= 20

To-do list

  • add an error handler for inexistent badges.
  • Should namespace app/models into Merit module.
  • rescue ActiveRecord::... should depend on ORM used
  • :value parameter (for star voting for example) should be configurable (depends on params[:value] on the controller).
  • Make fixtures for integration testing (now creating objects on test file!).
  • Rules should be cached? Calling * more than once
  • Add badges_sashes timestamps


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