title: Pushing app to Heroku failed because of django_comments
body: <p>I tried to push my project to Heroku and it failed because I couldn't find <code>django_comments</code>. Here is my log:</p>
  
  <pre><code>-----&gt; Using set buildpack heroku/python
  -----&gt; Python app detected
       $ pip install -r requirements.txt
       $ python manage.py collectstatic --noinput
         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 353, in execute_from_command_line
             utility.execute()
           File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 327, in execute
             django.setup()
           File "/app/.heroku/python/lib/python2.7/site-packages/django/__init__.py", line 18, in setup
             apps.populate(settings.INSTALLED_APPS)
           File "/app/.heroku/python/lib/python2.7/site-packages/django/apps/registry.py", line 85, in populate
             app_config = AppConfig.create(entry)
           File "/app/.heroku/python/lib/python2.7/site-packages/django/apps/config.py", line 90, in create
             module = import_module(entry)
           File "/app/.heroku/python/lib/python2.7/importlib/__init__.py", line 37, in import_module
             __import__(name)
         ImportError: No module named django_comments
   !     Error while running '$ python manage.py collectstatic --noinput'.
         See traceback above for details.
         You may need to update application code to resolve this error.
         Or, you can disable collectstatic for this application:
            $ heroku config:set DISABLE_COLLECTSTATIC=1
         https://devcenter.heroku.com/articles/django-assets
  ****** Collectstatic environment variables:
         CPLUS_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/vendor/include:/app/.heroku/python/include:
         SOURCE_VERSION=9698848ab6d9bab7f8c8e2181eb933f2619341e9
         PROFILE_PATH=/app/.profile.d/python.sh
         DEBUG_COLLECTSTATIC=1
         LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/vendor/lib:/app/.heroku/python/lib:
         CACHE_DIR=/app/tmp/cache
         PYTHONUNBUFFERED=1
         HEROKU_POSTGRESQL_AQUA_URL=postgres://wlxiltlrxwplzs:XDQANL2tlH_NdD_P_hUse2juCM@ec2-54-243-201-3.compute-1.amazonaws.com:5432/d6t4rugnogngm3
         PYHONHOME=/app/.heroku/python
         LD_LIBRARY_PATH=/app/.heroku/vendor/lib:/app/.heroku/vendor/lib:/app/.heroku/python/lib:
         BIN_DIR=/app/tmp/buildpacks/python/bin
         PATH=/app/.heroku/python/bin:/app/.heroku/vendor/bin::/usr/local/bin:/app/bin:/app/vendor/bundle/bin:/app/vendor/bundle/ruby/2.3.0/bin:/usr/local/bin:/usr/bin:/bin:/tmp/codon/vendor/bin:/app/tmp/buildpacks/python/vendor/bpwatch:/app/tmp/buildpacks/python/vendor/pip-pop
         RECOMMENDED_PYTHON_VERSION=python-2.7.11
         C_INCLUDE_PATH=/app/.heroku/vendor/include:/app/.heroku/vendor/include:/app/.heroku/python/include:
         ENABLE_COLLECTSTATIC=1
         PWD=/app
         LOG_FILE=/tmp/fifo20160525-3-183u9i6
         LANG=en_US.UTF-8
         STACK=cedar-14
         SHLVL=3
         REQUEST_ID=8504b0c1-bbd2-4360-ae76-7dfc10b78046
         HOME=/app
         BPWATCH_STORE_PATH=/app/tmp/cache/bpwatch.json
         PYTHONPATH=/app/
         BUILD_DIR=/app
         WARNINGS_LOG=/tmp/tmp.IxuQyzgYW1
         HEROKU_POSTGRESQL_NAVY_URL=postgres://ulkvhxkyxdewvx:PsGXzEe3oTDwGHgap5JINYgdpw@ec2-54-243-200-159.compute-1.amazonaws.com:5432/d77uogldogo1op
         USER_LOG_FILE=/tmp/fifo20160525-3-yjcxuf
         PKG_CONFIG_PATH=/app/.heroku/vendor/lib/pkgconfig:/app/.heroku/vendor/lib/pkgconfig:/app/.heroku/vendor/lib/pkg-config:/app/.heroku/vendor/lib/pkg-config:/app/.heroku/python/lib/pkg-config:
         DATABASE_URL=postgres://hvjyqvblijhpsk:GX4wjqN8bjSHOvwRB39nayAdZa@ec2-23-21-255-14.compute-1.amazonaws.com:5432/d2j3l0bc45qakf
         _=/usr/bin/env
   !     Push rejected, failed to compile Python app`
  </code></pre>
  
  <p>This is my <code>requiremenst.txt</code>:</p>
  
  <pre><code>dj-database-url==0.4.0 
  Django==1.9.2 
  gunicorn==19.4.5 
  psycopg2==2.6.1 
  whitenoise==2.0.6 
  </code></pre>