title: running (registering) prefect flows with parameters on schedule
body: <p>In <strong>prefect</strong> I would like to run flows with parameters on schedule.
  That sounds very natural to pass parameters, e.g. db credentials, right?</p>
  <p>I have created a flow with parameters that runs well as <code>prefect run -p flow.py --param db_config_path=somepath</code>, now I would like to register it as <code>prefect register --project project_name --path flow.py --name somename</code> (with server started and agent running) to run on schedule.</p>
  <p>However the server says:
  <code>
  graphql_1   | {&quot;severity&quot;: &quot;ERROR&quot;, &quot;name&quot;: &quot;prefect-server.api.flows&quot;, &quot;message&quot;: &quot;Failed to set schedule to active while creating flow (flow_id={flow_id}).&quot;, &quot;exc_info&quot;: &quot;Traceback (most recent call last):\n  File &quot;/prefect-server/src/prefect_server/api/flows.py&quot;, line 285, in create_flow\n    await api.flows.set_schedule_active(flow_id=flow_id)\n  File &quot;/prefect-server/src/prefect_server/api/flows.py&quot;, line 564, in set_schedule_active\n    raise ValueError(&quot;Can not schedule a flow that has required parameters.&quot;)\nValueError: Can not schedule a flow that has required parameters.&quot;}
  </code></p>
  <p>Moreover I found this:</p>
  <p><a href="https://github.com/PrefectHQ/prefect/issues/380" rel="nofollow noreferrer">https://github.com/PrefectHQ/prefect/issues/380</a></p>
  <p>So it seems that flows with parameters are out of <strong>prefect</strong> paradigm? How do I pass db creds to the flows in this case?</p>