def target!(addr)
      unless (address = Address.first(:address => addr))
        raise("unknown address #{addr.dump}")
      end

      return Target.first_or_create(:campaign => self, :address => address)
    end
def target!(addr)
      unless (address = Address.first(:address => addr))
        raise("unknown address #{addr.dump}")
      end

      return Target.first_or_create(:campaign => self, :address => address)
    end
Adds an address to the campaign.

 @param [String] addr
   The address that will be targeted.

 @return [Target]
   The new target of the campaign.

 @raise [RuntimeError]
   The given address could not be found.

 @since 1.0.0

 @api public