title: How to make automatic migrations on Phoenix / Ecto?
body: <p>I come from a python / django background where a simple <code>python manage.py makemigrations</code> was generating my migration. </p>
  
  <p>Now the question is, with Ecto, I do not find commands like that. It seems i have to use <code>mix ecto.gen.migration</code> and then fill the migration manually. It will not detect changes in my model automatically, I have to fill it manually.</p>
  
  <p>Do you have any ideas how to generate the migration almost automatically (for instance if I am adding a field in an existing model).</p>