Merge pull request #64 from eblume/patch-1

Fix "RemovedInDjango40Warning: force_text()..." warning

redis_sessions/session.py

@@ -3,7 +3,7 @@
 try:
     from django.utils.encoding import force_unicode
 except ImportError:  # Python 3.*
-    from django.utils.encoding import force_text as force_unicode
+    from django.utils.encoding import force_str as force_unicode
 from django.contrib.sessions.backends.base import SessionBase, CreateError
 from redis_sessions import settings