title: .ini file load environment variable
body: <p>I am using <a href="http://alembic.readthedocs.io/en/latest/" rel="noreferrer">Alembic</a> for migrations implementation in a <code>Flask</code> project. There is a <code>alembic.ini</code> file where the database configs must be specified:</p>
  
  <p><code>sqlalchemy.url = driver://user:password@host/dbname</code></p>
  
  <p>Is there a way to specify the parameters from the environment variables? I've tried to load them in this way <code>$(env_var)</code> but with no success. Thanks!</p>