Rails 3 merging scope with OR

gistfile1.rb

# By Steve Leung
# [email protected]

class ActiveRecord::Relation

  # temporarily hack for allowing combining scopes with OR
  # doesn't add the join tables so need to use .includes manually
  # ie. Jobship.includes(:job).or(Jobship.accepted, Jobship.declined).count
  def or(*scopes)
    clauses = *scopes.map do |relation| 
      clause = relation.arel.where_clauses.map { |clause| "(#{clause})" }.join(' AND ')
      "(#{clause})" 
    end.join(' OR ')

    where clauses
  end
end