hor"></a>Migration</h2><p>A &quot;migration&quot; is a script in <code>app/db/migrate</code> that can be used to either create or destroy the table for a model.</p><h2 id="model"><a href="#model" class="anchor"></a>Model</h2><p>A &quot;model&quot; is either a source code file/module in the <code>app/models</code> file or a record type <code>t</code> defined at the top of some such file (which should one should be clear from context). These define entities (for instance a user, or a blog post) and business l