title: foreignkey (user) in models
body: <p>I read the docs and this post... <a href="https://stackoverflow.com/questions/7309588/django-foreign-key-to-user-model">Django - Foreign Key to User model</a></p>
  <p>I followed what it said and I still cannot get it to work. When I try to run the migrations I get this error in the traceback...</p>
  <pre><code>django.db.utils.ProgrammingError: column &quot;author_id&quot; cannot be cast automatically to type integer
  HINT:  You might need to specify &quot;USING author_id::integer&quot;.
  </code></pre>
  <p>I just don't know how to go about fixing that error.</p>
  <pre class="lang-py prettyprint-override"><code>from django.db import models
  from django.contrib.auth.models import User
  
  # Create your models here.
  class BlogCategory(models.Model):
      '''model for categories'''
  
      title = models.CharField(max_length=30)
      description = models.CharField(max_length=100)
  
  
  class BlogPost(models.Model):
      '''a model for a blog post'''
  
      author = models.ForeignKey(User)
      date = models.DateField()
      title = models.CharField(max_length=100)
      post = models.TextField()
  </code></pre>