title: Connecting to locally postgresql using sqlalchemy
body: <p>Definitely a beginner here.  I'm having issues connecting to postgresql database run locally on a macosx machine using postgres.app and sqlalchmey:  </p>
  
  <p>import psycopg2
  import sqlalchemy</p>
  
  <p>engine = sqlalchemy.create_engine('postgresql://localhost/practice.db')
  engine.connect()</p>
  
  <p>Returns:
  <strong>OperationalError: (OperationalError) FATAL:  database "practice.db" does not exist
   None None</strong></p>
  
  <p>Thanks,
  Evan</p>