bar.rb

# app/models/bar.rb
class Bar < ActiveRecord::Base
  include Searchable
end

foo.rb

# app/models/foo.rb
class Foo < ActiveRecord::Base
  include Searchable
end

searchable.rb

# app/models/concern/searchable.rb
module Searchable
  extend ActiveSupport::Concern
  
  included do
    scope :term, ->(term) do
      where { name.like("%#{term}%") }
    end
  end
end

searchable_spec.rb

# spec/concerns/searchable_spec.rb
require 'spec_helper'

describe Searchable do
end