title: Heroku not recognizing NumPy in requirements.txt
body: <p>I've been having difficulty trying to run <strong><a href="http://ocelma.net/software/python-recsys/build/html/installation.html" rel="nofollow">python-recsys</a></strong> with Flask on Heroku</p>
  
  <p>One of the requirements for python-recsys is that it requires numpy</p>
  
  <p>My requirements.txt is </p>
  
  <pre><code>decorator==4.0.4
  numpy==1.6.2
  Flask==0.10.1
  itsdangerous==0.24
  Jinja2==2.8
  MarkupSafe==0.23
  networkx==1.10
  git+https://github.com/ocelma/python-recsys.git
  scipy==0.16.1
  Werkzeug==0.10.4
  wheel==0.24.0
  Divisi2==2.2.5
  </code></pre>
  
  <p>Outputs</p>
  
  <pre><code>Counting objects: 4434, done.
  Delta compression using up to 4 threads.
  Compressing objects: 100% (4353/4353), done.
  Writing objects: 100% (4434/4434), 33.17 MiB | 470 KiB/s, done.
  Total 4434 (delta 394), reused 0 (delta 0)
  remote: Compressing source files... done.
  remote: Building source:
  remote: 
  remote: -----&gt; Removing .DS_Store files
  remote: -----&gt; Python app detected
  remote: -----&gt; Installing runtime (python-2.7.10)
  remote: -----&gt; Installing dependencies with pip
  remote:        Collecting git+https://github.com/ocelma/python-recsys.git          (from -r requirements.txt (line 8))
  remote:          Cloning https://github.com/ocelma/python-recsys.git to    /tmp/pip-nCYxck-build
  remote:        Collecting decorator==4.0.4 (from -r requirements.txt (line 1))
  remote:          Downloading decorator-4.0.4-py2.py3-none-any.whl
  remote:        Collecting numpy==1.6.2 (from -r requirements.txt (line 2))
  remote:          Downloading numpy-1.6.2.tar.gz (2.6MB)
  remote:        Collecting Flask==0.10.1 (from -r requirements.txt (line 3))
  remote:          Downloading Flask-0.10.1.tar.gz (544kB)
  remote:        Collecting itsdangerous==0.24 (from -r requirements.txt (line 4))
  remote:          Downloading itsdangerous-0.24.tar.gz (46kB)
  remote:        Collecting Jinja2==2.8 (from -r requirements.txt (line 5))
  remote:          Downloading Jinja2-2.8-py2.py3-none-any.whl (263kB)
  remote:        Collecting MarkupSafe==0.23 (from -r requirements.txt (line 6))
  remote:          Downloading MarkupSafe-0.23.tar.gz
  remote:        Collecting networkx==1.10 (from -r requirements.txt (line 7))
  remote:          Downloading networkx-1.10.tar.gz (1.2MB)
  remote:        Collecting scipy==0.16.1 (from -r requirements.txt (line 9))
  remote:          Downloading scipy-0.16.1.tar.gz (12.2MB)
  remote:        Collecting Werkzeug==0.10.4 (from -r requirements.txt (line 10))
  remote:          Downloading Werkzeug-0.10.4-py2.py3-none-any.whl (293kB)
  remote:        Collecting wheel==0.24.0 (from -r requirements.txt (line 11))
  remote:          Downloading wheel-0.24.0-py2.py3-none-any.whl (63kB)
  remote:        Collecting Divisi2==2.2.5 (from -r requirements.txt (line 12))
  remote:          Downloading Divisi2-2.2.5.tar.gz (10.9MB)
  remote:            Complete output from command python setup.py egg_info:
  remote:            This package requires NumPy.
  remote:            
  remote:            On a Debian / Ubuntu system, you can run:
  remote:              sudo apt-get install python-numpy python-dev
  remote:            
  remote:            Otherwise it will probably suffice to:
  remote:              sudo easy_install numpy
  remote:            
  remote:            
  remote:            ----------------------------------------
  remote: Command "python setup.py egg_info" failed with error code 1 in /tmp/pip-    build-U6idSN/Divisi2
  remote: 
  remote:  !     Push rejected, failed to compile Python app
  </code></pre>
  
  <p>It appears from the output that numpy was installed (Line 2 )
  but it outputs as uninstalled</p>
  
  <p>I've tried different variations including different versions of numpy
  I've tried putting the numpy requirement in different positions in the requirements.txt</p>
  
  <p>Any ideas as to what is causing this error?
  Is there a better way to install numpy?</p>