title: bundling not working
body: <p>I am new to flask and angularjs. I am trying to use bundle(assets) according to instructions provided <a href="http://flask-assets.readthedocs.org/en/latest/" rel="nofollow">here</a>.</p>
  
  <p>I have installed the required jsmin and am calling my filter in the html part accordingly
  <code>
  {% assets "common_js" %}
      &lt;script src="{{ ASSET_URL }}"&gt;&lt;/script&gt;
  {% endassets %}</code></p>
  
  <p>Here common_js bundle has been declared and registered.</p>
  
  <pre><code>from flask.ext.assets import Environment, Bundle
  common_js = Bundle("datepicker.js",filters='jsmin', output='output.js')
  assets_env.register('common_js',common_js)
  </code></pre>
  
  <p>The output that I can see on the server terminal is 
  <code>
  INFO     2015-06-30 02:18:44,606 module.py:790] default: "GET /%7B%7B%20ASSET_URL%20%7D%7D HTTP/1.1" 404 2322
  </code>
  Can anyone point out what I am missing please? Any help is appreciated.
  Thanks.</p>