Fixed one typo in response_helpers which caused is_admin context variable not to work correctly.
Created new checkLinkNameForId function that checks if link_name is correct when creating new user and modifying existing one. This is now used for validation instead of doesLinkNameBelongToId in UserForm clean_link_name function. The previous validation function didn't allow to create new users and modify linkname of existing ones. Additionally I created new doesLinkNameExist helper function.
from django import http
def index(request):
r = http.HttpResponse('<h1>Django examples</h1><ul>')
r.write('<li><a href="hello/html/">Hello world (HTML)</a></li>')
r.write('<li><a href="hello/text/">Hello world (text)</a></li>')
r.write('<li><a href="hello/write/">HttpResponse objects are file-like objects</a></li>')
r.write('<li><a href="hello/metadata/">Displaying request metadata</a></li>')
r.write('<li><a href="hello/getdata/">Displaying GET data</a></li>')
r.write('<li><a href="hello/postdata/">Displaying POST data</a></li>')
r.write('</ul>')
return r