add logout route

app/auth.py

@@ -57,6 +57,15 @@ def create_session(user_id, temporary=False):
         'expires_at': int(time.time()) + (expires_days * 24 * 60 * 60),
     })
 
+def revoke_session(user_id):
+    if not is_logged_in():
+        return
+    sess = Sessions.find({'key': session['pyrom_session_key']})
+    if not sess:
+        return
+    sess.delete()
+    session.clear()
+
 def parse_username(username: str) -> Tuple[str, str]:
     """first is the unmodified name/display name, second is username"""
     if len(username) < 3: