title: Python - Flask assets fails to compress my asset files
body: <p>noob here. I was trying to crunch my javascript files using <a href="http://elsdoerfer.name/docs/flask-assets/" rel="nofollow">flask assets</a> but unfortunately my view rendered all the javascript files as <strong>separate links</strong> and not as <strong>one</strong> minified file.</p>
  
  <p>Here is my code and file structure. Please help me learn.</p>
  
  <pre><code>import os
  from flask import Flask
  from flask.ext.assets import Environment , Bundle
  from main.views import main
  from webassets.loaders import PythonLoader
  
  app = Flask(__name__)
  assets = Environment(app)
  
  app.register_blueprint(main, url_prefix='/')
  
  #Compress All Assets
  js = Bundle('javascripts/main.js',
              'javascripts/plugins.js',
              'javascripts/vendor/jquery-1.9.1.min.js',
              'javascripts/vendor/modernizr-2.6.2.min.js',
  
              filters='jsmin', output='gen/packedjs.js')
  assets.register('js_all', js)
  
  css = Bundle('stylesheets/css/main.css',
              'stylesheets/css/normalize.css',
              filters='sass,less,cssmin', output='gen/packedcss.css')
  assets.register('css_all', css)
  </code></pre>
  
  <p>This is my code in index.html</p>
  
  <pre><code>{% assets "css_all" %}
          &lt;link rel="stylesheet" href="{{ ASSET_URL }}"&gt;
  {% endassets %}
  
  {% assets "js_all" %}
         &lt;script type="text/javascript" src="{{ ASSET_URL }}"&gt;&lt;/script&gt;
  {% endassets %}
  </code></pre>
  
  <p>My file structure of css and javascript files.</p>
  
  <ul>
  <li>static
  <ul>
  <li>gen (folder)</li>
  </ul></li>
  <li>Javascript (folder)
  <ul>
  <li>javascript file 1</li>
  <li>javascript file 2</li>
  <li>javascript file 3</li>
  </ul></li>
  </ul>