title: Flask + SqlAlchemy ALTER table
body: <p>I'm developing a web application based on Flask + SqlAlchemy + MySQL and I followed <a href="https://stackoverflow.com/a/22422817/2024665">that answer</a>.
  I have to change my model so I need to alter the db table adding a column, but <strong>I don't want to lose the stored data</strong> dropping and recreating it. </p>
  
  <p>I read something about Flask-Migrate and Alembic... are they essential to solve my problem? What can I do?</p>