feat: handling for integrity errors

Resolves: #7

src/exceptions.py

@@ -13,3 +13,12 @@ class UnprocessableContent(HTTPException):
 			status_code=status.HTTP_422_UNPROCESSABLE_CONTENT,
 			detail=detail,
 		)
+
+
+class Conflict(HTTPException):
+	def __init__(self, message: Optional[str] = None) -> None:
+		detail = "Conflict" if not message else message
+		super().__init__(
+			status_code=status.HTTP_409_CONFLICT,
+			detail=detail,
+		)