title: Django postgresql Datefield error
body: <p>I'm migrating a mysql database to postgresql in Django and have encountered the following error:</p>
  
  <pre><code>django.db.utils.ProgrammingError: column "end_date" cannot be cast automatically to type timestamp with time zone
  HINT:  Specify a USING expression to perform the conversion.
  </code></pre>
  
  <p>The error is referring the this line in my model:</p>
  
  <pre><code>end_date = models.DateField()
  </code></pre>
  
  <p>The solutions online that I have found have been altering the sql directly, is there a way to correct the model in Django to work with the postgresql database?</p>
  
  <p>Here is the full error, which occurs on migration:</p>
  
  <pre><code>Running migrations:
    Applying catalog.0006_auto_20141121_0419...Traceback (most recent call last):
    File "manage.py", line 10, in &lt;module&gt;
      execute_from_command_line(sys.argv)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 385, in execute_from_command_line
      utility.execute()
    File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 377, in execute
      self.fetch_command(subcommand).run_from_argv(self.argv)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 288, in run_from_argv
      self.execute(*args, **options.__dict__)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 338, in execute
      output = self.handle(*args, **options)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/commands/migrate.py", line 161, in handle
      executor.migrate(targets, plan, fake=options.get("fake", False))
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/migrations/executor.py", line 68, in migrate
      self.apply_migration(migration, fake=fake)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/migrations/executor.py", line 102, in apply_migration
      migration.apply(project_state, schema_editor)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/migrations/migration.py", line 108, in apply
      operation.database_forwards(self.app_label, schema_editor, project_state, new_state)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/migrations/operations/fields.py", line 139, in database_forwards
      schema_editor.alter_field(from_model, from_field, to_field)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/schema.py", line 455, in alter_field
      self._alter_field(model, old_field, new_field, old_type, new_type, old_db_params, new_db_params, strict)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/schema.py", line 601, in _alter_field
      params,
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/schema.py", line 103, in execute
      cursor.execute(sql, params)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/utils.py", line 81, in execute
      return super(CursorDebugWrapper, self).execute(sql, params)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
      return self.cursor.execute(sql, params)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/utils.py", line 94, in __exit__
      six.reraise(dj_exc_type, dj_exc_value, traceback)
    File "/app/.heroku/python/lib/python2.7/site-packages/django/db/backends/utils.py", line 65, in execute
      return self.cursor.execute(sql, params)
  django.db.utils.ProgrammingError: column "end_date" cannot be cast automatically to type timestamp with time zone
  HINT:  Specify a USING expression to perform the conversion.
  </code></pre>