Support for GCM stored messages.

// FREEBIE

src/main/java/org/whispersystems/textsecuregcm/entities/GcmRegistrationId.java

@@ -25,9 +25,15 @@ public class GcmRegistrationId {
   @NotEmpty
   private String gcmRegistrationId;
 
+  @JsonProperty
+  private boolean webSocketChannel;
+
   public String getGcmRegistrationId() {
     return gcmRegistrationId;
   }
 
+  public boolean isWebSocketChannel() {
+    return webSocketChannel;
+  }
 }