title: How to fix error "ERROR: Command errored out with exit status 1: python." when trying to install django-heroku using pip
body: <p>I am trying to install django-heroku using pip, but it keeps running into an error.</p>
  <p>I have seen suggestions telling me to make sure my Python version in Heroku is up to date. I have already done that. After pushing to Heroku master, I ran the install command, but it gives me the following errors.</p>
  <pre><code>pip install django-heroku
  </code></pre>
  <p>Error:</p>
  <pre class="lang-none prettyprint-override"><code>ERROR: Command errored out with exit status 1:
  command: /Users/user/Dev/trydjango/new_env/bin/python -c 'import
  sys, setuptools, tokenize; sys.argv[0] =
  '&quot;'&quot;'/private/var/folders/xl/s533dc515qs8sd3tpg7y5ty80000gp/T/pip-
  install-xqsix26g/psycopg2/setup.py'&quot;'&quot;';
  
  egg_info --egg-base pip-egg-info
       cwd:
  /private/var/folders/xl/s533dc515qs8sd3tpg7y5ty80000gp/T/pip-
  install-xqsix26g/psycopg2/
  Complete output (23 lines):
  running egg_info
  creating pip-egg-info/psycopg2.egg-info
  writing pip-egg-info/psycopg2.egg-info/PKG-INFO
  writing dependency_links to pip-egg-info/psycopg2.egg-
  info/dependency_links.txt
  writing top-level names to pip-egg-info/psycopg2.egg-
  info/top_level.txt
  writing manifest file 'pip-egg-info/psycopg2.egg-info/SOURCES.txt'
  
  Error: pg_config executable not found.
  
  pg_config is required to build psycopg2 from source.  Please add t .   he directory
  containing pg_config to the $PATH or specify the full executable
  path with the
  option:
  
      python setup.py build_ext --pg-config /path/to/pg_config build ...
  
  or with the pg_config option in 'setup.cfg'.
  
  If you prefer to avoid building psycopg2 from source, please
  install the PyPI
  'psycopg2-binary' package instead.
  
  For further information please check the 'doc/src/install.rst' file
  (also at
  &lt;http://initd.org/psycopg/docs/install.html&gt;).
  
  ----------------------------------------
  ERROR: Command errored out with exit status 1: python setup.py
  egg_info Check the logs for full command output.
  </code></pre>