fix: for banned user check

Merge pull request #107 from d-Rickyy-b/dev

Author: devcarron

.travis.yml

@@ -0,0 +1,9 @@
+## custom_strings directory
+
+This directory was created to add translations on the fly, when the bot runs inside a docker container.
+
+```
+└───lang
+    ├───custom_strings  // custom translations
+    └───strings         // translations provided by the package maintainer
+```

blackjackbot/lang/custom_strings/README.md

@@ -1 +1 @@
-python-telegram-bot==13.1
+python-telegram-bot>=13.5

requirements.txt

@@ -1,13 +1,23 @@
 # -*- coding: utf-8 -*-
+import logging
+
 from telegram.ext import TypeHandler
 
 import database
 
 
 class BannedUserHandler(TypeHandler):
+    logger = logging.getLogger()
 
     def check_update(self, update):
         db = database.Database()
-        if db.is_user_banned(update.effective_user.id):
+        user = update.effective_user
+
+        if user is None:
+            self.logger.warning(f"User is None! Update: {update}")
+            return False
+
+        if db.is_user_banned(user.id):
             return True
+
         return False