Rewrite to Quart web-framework, refactor code.

yellow/__init__.py

@@ -0,0 +1,13 @@
+from quart import session, abort
+
+from functools import wraps
+
+
+def login_required(func):
+    @wraps(func)
+    async def wrapper(*args, **kwargs):
+        user = session.get('user')
+        if not isinstance(user, dict):
+            abort(403)
+        return await func(*args, **kwargs)
+    return wrapper