Added support for Do Not Disturb UserStatus

src/Discord.Net/Entities/Users/UserStatus.cs

@@ -5,6 +5,7 @@
         Unknown,
         Online,
         Idle,
-        Offline
+        Offline,
+        DoNotDisturb
     }
 }

src/Discord.Net/Net/Converters/UserStatusConverter.cs

@@ -21,6 +21,8 @@ namespace Discord.Net.Converters
                     return UserStatus.Idle;
                 case "offline":
                     return UserStatus.Offline;
+                case "dnb":
+                    return UserStatus.DoNotDisturb;
                 default:
                     throw new JsonSerializationException("Unknown user status");
             }
@@ -39,6 +41,9 @@ namespace Discord.Net.Converters
                 case UserStatus.Offline:
                     writer.WriteValue("offline");
                     break;
+                case UserStatus.DoNotDisturb:
+                    writer.WriteValue("dnb");
+                    break;
                 default:
                     throw new JsonSerializationException("Invalid user status");
             }