title: How to use pipenv to install package from github
body: <p>Using pipenv to install the spaCy package from github with</p>
  
  <pre><code>pipenv install -e git+https://github.com/explosion/spaCy#egg=spacy
  </code></pre>
  
  <p>I run into two problems:</p>
  
  <p>(1) Install fails, because the following packages need to be installed before: <code>cython, preshed, murmurhash, thinc</code>. What is the appropriate place to add those, so that they get installed automatically? I tried <code>setup_requires</code> in <code>setup.py</code> but that didn't work.</p>
  
  <p>(2) After installing the required packages the install runs through, but the creation of the Pipfile.lock fails with:</p>
  
  <pre><code>Adding -e git+https://github.com/explosion/spaCy#egg=spacy to Pipfile's [packages]…
  Pipfile.lock not found, creating…
  Locking [dev-packages] dependencies…
  Locking [packages] dependencies…
  _dependencies(best_match):
    File "/home/me/.local/lib/python3.5/site-packages/pipenv/patched/piptools/resolver.py", line 275, in _iter_dependencies
      for dependency in self.repository.get_dependencies(ireq):
    File "/home/me/.local/lib/python3.5/site-packages/pipenv/patched/piptools/repositories/pypi.py", line 202, in get_dependencies
      legacy_results = self.get_legacy_dependencies(ireq)
    File "/home/me/.local/lib/python3.5/site-packages/pipenv/patched/piptools/repositories/pypi.py", line 221, in get_legacy_dependencies
      dist = ireq.get_dist()
    File "/home/me/.local/lib/python3.5/site-packages/pipenv/vendor/pip9/req/req_install.py", line 1069, in get_dist
      egg_info = self.egg_info_path('').rstrip('/')
    File "/home/me/.local/lib/python3.5/site-packages/pipenv/vendor/pip9/req/req_install.py", line 515, in egg_info_path
      'No files/directories in %s (from %s)' % (base, filename)
  pip9.exceptions.InstallationError: No files/directories in None (from )
  </code></pre>
  
  <p>What is the correct way to do this?</p>