title: Can't install flask_sqlalchemy ->ImportError: No module named flask_sqlalchemy
body: <p>I have flask installed via virtualenv, and I used <code>source bin/activate</code> to use flask. Flask returns fine, but I cannot import sqlalchemy or flask-sqlalchemy (or flask_sqlalchemy) at all. </p>
  
  <p>I used <code>pip list</code> and it shows that both installations are there. My Mac is a fresh install, and I have found no resolutions online. I feel like this is a $PATH error, but I am not certain. Any help at all? </p>
  
  <pre><code>(project) ➜  project pip list    
  click (6.4)
  Flask (0.11.dev0)
  Flask-SQLAlchemy (2.1)
  itsdangerous (0.24)
  Jinja2 (2.8)
  MarkupSafe (0.23)
  pip (8.1.1)
  setuptools (20.6.7)
  SQLAlchemy (1.0.12)
  Werkzeug (0.11.5)
  wheel (0.29.0)
  
  (project) ➜  project flask-sqlalchemy
  zsh: command not found: flask-sqlalchemy
  (project) ➜  project flask_sqlalchemy
  zsh: command not found: flask_sqlalchemy
  (project) ➜  project sqlalchemy
  zsh: command not found: sqlalchemy
  </code></pre>