I am using Peewee and I need to create migration file for my database
<p>How should I start here, I am a bit confused.</p>

<p>I have database schemas which are newer than the old database.</p>

<p>I have seen Arnold package, where there are two methods <code>arnold up</code> and <code>arnold down</code>. There are migration files where you can add all your database queries. But still those changes I can see and I can add in <code>up</code> like <code>create table</code> or <code>alter table</code> and in <code>arnold down</code> I can add <code>drop table</code> or <code>alter table</code>. But my migration will become only for that database.</p>

<p>I want to understand what does database migration should contain. And what does it do. I will be very grateful if someone explain me <code>database migration</code> and push me in the right direction of peewee, psql database migration</p>