title: Postgres Sequences as Default Value for Django Model Field
body: <p>I have a PostgreSQL database that is being used by a front-end application built with Django, but being populated by a scraping tool in Node.js. I have made a <code>sequence</code> that I want to use across two different tables/entities, which can be accessed by a function (<code>nexval(serial)</code>) and is called on every insert. This is not the primary key for these tables, but simply a way to maintain order through some metadata. Using it in Node.js during the insertion of the data into the tables is trivial, as I am using raw SQL queries. However, I am struggling with how to represent this using Django models. There does not seem to be any way to associate this Postgres function with a model's field.</p>
  
  <p>Question:
  Is there a way to use a Postgres function as the default value of a Django model field?</p>