[New Feature] Rest API implementation to showcase the OpenDBM features

rest_api/app/schemas/token.py

@@ -0,0 +1,9 @@
+from pydantic import BaseModel
+from typing import Union
+
+class Token(BaseModel):
+    access_token: str
+    token_type: str
+
+class TokenData(BaseModel):
+    username: Union[str, None] = None