title: Find items within a certain range of given coordinate
body: <p>I have a django based web app which stores locations. </p>
  
  <p>I have an android mobile app which pulls the locations from the web app and saves locations to the web app. The locations returned back to me I load on a mapoverlay in my app.</p>
  
  <p>I would like to send my current coordinates and return a list of locations which are within a certain range. For example I send my location and get back items within a radius of 2km. (Similar to how the Google Places API works, just searching my data).</p>
  
  <p>It is probably best to send the location coordinates and do all this logic in my python django app, Then return a list of correct locations and just display the places on my map. </p>
  
  <p>I don't know where to begin doing this.
  How can I filter out my stored locations within certain radius(km) based off a given set of coordinates?</p>