title: airflow DAG seems to be missing
body: <p>I have Airflow scheduler and Webserver service running on different instances. When I put the DAG on Scheduler(/usr/local/airflow/dag), I can see the DAG in the web UI . But when I try to click it I get the error </p>
  
  <p><strong>DAG "tutorial" seems to be missing.</strong>.</p>
  
  <p>If I copy the same file to Webserver, I am done away with the message. So basically I need to copy my dag to both Scheduler and Webserver</p>
  
  <p>I am a newbie trying to configure airflow server with Webserver, Scheduler,2 worker instances. Did I missed something ? How can I share the "DAG" folder with scheduler and Webserver so that they are able to see the same DAG.</p>