1. fixed redir issue seen earlier

 -  Issue: in case referrer was null, app redirected to /None
 -  Fix: in case of redir value in request, set session to redir value
         else, set session to default referrer (from vars.py))

app/__init__.py

@@ -40,13 +40,7 @@ def create_app(config_name):
         if 'user' not in session:
             session["user"] = get_authorized_user()
 
-        if "redir" in request.args and 'return_url' not in session: # check for redir arg in url
-            session['return_url'] = request.args.get("redir")
-
-        elif "redir" not in request.args and 'return_url' not in session:
-            session['return_url'] = vars.default_referrer
-        else:
-            session['return_url'] = request.referrer
+        session['return_url'] = request.args.get('redir', vars.default_referrer)
 
         return render_template('auth/SignUp.html', room_id=session['uid'],
                                username=session['user'].get('username'),