title: Flask Sql-alchemy not dropping tables created by alembic
body: <p>I have flask application with Flask-migrate. Running <code>db upgrade</code> creates following tables:</p>
  
  <pre><code>              List of relations
  Schema |      Name       | Type  |  Owner   
  -------+-----------------+-------+----------
  public | alembic_version | table | postgres
  public | operations      | table | postgres
  public | rule_values     | table | postgres
  public | rules           | table | postgres
  public | shares          | table | postgres
  </code></pre>
  
  <p>But when I drop all tables with:</p>
  
  <pre><code>db = SQLAlchemy(app)
  db.drop_all()
  </code></pre>
  
  <p>I got this:</p>
  
  <pre><code>              List of relations
  Schema |      Name       | Type  |  Owner   
  -------+-----------------+-------+----------
  public | alembic_version | table | postgres
  </code></pre>
  
  <p>Is there solution to drop all tables (even <code>alembic_version</code>)?</p>