added logs

flutter/lib/models/message.dart

@@ -35,13 +35,13 @@ class Message {
       senderUserID: json['sender_user_id'] as String,
       channelInternalName: json['channel_internal_name'] as String,
       channelID: json['channel_id'] as String,
-      senderName: json['sender_name'] as String,
+      senderName: json['sender_name'] as String?,
       senderIP: json['sender_ip'] as String,
       timestamp: json['timestamp'] as String,
       title: json['title'] as String,
-      content: json['content'] as String,
+      content: json['content'] as String?,
       priority: json['priority'] as int,
-      userMessageID: json['usr_message_id'] as String,
+      userMessageID: json['usr_message_id'] as String?,
       usedKeyID: json['used_key_id'] as String,
       trimmed: json['trimmed'] as bool,
     );