Store a last_visit time on the Account thing.

r2/r2/models/account.py

@@ -225,6 +225,9 @@ class Account(Thing):
 
         LastModified.touch(self._fullname, "Visit")
 
+        self.last_visit = int(time.time())
+        self._commit()
+
     def make_cookie(self, timestr=None):
         if not self._loaded:
             self._load()