Fix errors

[ozanpekmezci]

user_id in the Cluster model is an integer field and user_id of Ratings is a char field. That's why when you try to visit a page of cluster (for example http://localhost:8000/analytics/cluster/3/) Django was throwing an error because the code was comparing integers and strings. Now, integer list is converted to a string list first and strings are compared to strings.

[kimfalk]

Thank you for your pullrequest.

The nlkt should be there. So that is good.

The clustering view in Django is working fine in my version. So I will investigate it in more detail before merging.