Add scope with_role to Role Model

role_model.rb

# Copy from easy_roles
# https://github.com/platform45/easy_roles/blob/cf9c5f6e5db46adf8c48cc1a2e43c83ece3c2f4f/lib/methods/bitmask.rb
#
# Put it to config/initializers/
module RoleModel
  class << self
    alias_method :origin_included, :included
  end

  def self.included(base)
    origin_included(base)

    base.class_eval do
      scope :with_role, proc { |role|
        role = role.to_sym
        raise ArgumentError unless valid_roles.include? role
        role_bit_index = valid_roles.index(role)
        valid_mask_integers = (0..2**valid_roles.count-1).select {|i| i[role_bit_index] == 1 }
        where(roles_attribute_name => valid_mask_integers)
      }
    end

  end
end