has_many :access_grants, :class_name => Doorkeeper.config.access_grant_model.name, :foreign_key => :resource_owner_id
has_many :access_tokens, :class_name => Doorkeeper.config.access_token_model.name, :foreign_key => :resource_owner_id
has_many :access_grants, :class_name => Doorkeeper.config.access_grant_model.name, :foreign_key => :resource_owner_id
has_many :access_tokens, :class_name => Doorkeeper.config.access_token_model.name, :foreign_key => :resource_owner_id