Create update_username functions for category and table.

classes/table.py

@@ -162,3 +162,24 @@ class Table:
             str: string of json representation of Table
         """
         return json.dumps(self.to_dict(), indent=4)
+
+    def update_username(self, old_username: str, new_username: str) -> bool:
+        """
+        Calls Category update_username function for each category. Returns true if a category
+        was updated to inform if the table message needs rewritten.
+
+        Args:
+            old_username (str): Username to replace. Sent to Category function
+            new_username (str): Username to replace with. Sent to Category function
+
+        Returns:
+            bool: True if category was updated and requires message update
+        """
+
+        ret_val: bool = False
+
+        for category in self.categories:
+            if category.update_username(old_username, new_username):
+                ret_val &= True
+
+        return ret_val