[add]: enforce content type json

app/errors/__init__.py

@@ -1 +1 @@
-from .handlers import bad_request, method_not_allowed, not_found
+from .handlers import method_not_allowed, unsupported_media_type

app/errors/handlers.py

@@ -9,3 +9,6 @@ def not_found(error):
 
 def bad_request(error):
     return ResponseHelper.bad_request(message="Bad Request")
+
+def unsupported_media_type(error):
+    return ResponseHelper.error(message="Unsupported Media Type", status_code=415)