title: DAG not visible in Web-UI
body: <p>I am new to <code>Airflow</code>. I am following a tutorial and written following code.</p>
  
  <pre><code>from airflow import DAG
  from airflow.operators.python_operator import PythonOperator
  from datetime import datetime, timedelta
  from models.correctness_prediction import CorrectnessPrediction
  
  default_args = {
      'owner': 'abc',
      'depends_on_past': False,
      'start_date': datetime.now(),
      'email': ['abc@xyz.com'],
      'email_on_failure': False,
      'email_on_retry': False,
      'retries': 1,
      'retry_delay': timedelta(minutes=5)
  }
  
  def correctness_prediction(arg):
      CorrectnessPrediction.train()
  
  dag = DAG('daily_processing', default_args=default_args)
  
  task_1 = PythonOperator(
      task_id='print_the_context',
      provide_context=True,
      python_callable=correctness_prediction,
      dag=dag)
  </code></pre>
  
  <p>On running the script, it doesn't show any errors but when I check for <code>dags</code> in <code>Web-UI</code> it doesn't show under <strong>Menu</strong>-><strong>DAGs</strong></p>
  
  <p><a href="https://i.stack.imgur.com/PeBid.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PeBid.png" alt="enter image description here"></a></p>
  
  <p>But I can see the scheduled <code>job</code> under <strong>Menu</strong>-><strong>Browse</strong>-><strong>Jobs</strong></p>
  
  <p><a href="https://i.stack.imgur.com/PB1xe.png" rel="noreferrer"><img src="https://i.stack.imgur.com/PB1xe.png" alt="enter image description here"></a></p>
  
  <p>I also cannot see anything in $AIRFLOW_HOME/dags. Is it supposed to be like this only? Can someone explain why?</p>