message: Add optional docker_image
diff: @@ -15,7 +15,7 @@ class Rule(ABC):
  self.set_user_defined_parameters(**user_defined_parameters)
  def set_core_parameters(
  - self, payment_cycle_length, start_block, end_block, subgraph_config_locations
  + self, payment_cycle_length, start_block, end_block, subgraph_config_locations, docker_image=None
  ):
  self.payment_cycle_length = payment_cycle_length
  self.start_block = start_block
  