remove MessageUrl model.

app/src/main/java/chat/rocket/android/model/ddp/Message.java

 package chat.rocket.android.model.ddp;
 
 import chat.rocket.android.model.SyncState;
-import io.realm.RealmList;
 import io.realm.RealmObject;
 import io.realm.annotations.PrimaryKey;
 import org.json.JSONException;
@@ -24,7 +23,7 @@ public class Message extends RealmObject {
   private User u;
   private boolean groupable;
   private String attachments; //JSONArray.
-  private RealmList<MessageUrl> urls;
+  private String urls; //JSONArray.
 
   public String get_id() {
     return _id;
@@ -98,11 +97,11 @@ public class Message extends RealmObject {
     this.attachments = attachments;
   }
 
-  public RealmList<MessageUrl> getUrls() {
+  public String getUrls() {
     return urls;
   }
 
-  public void setUrls(RealmList<MessageUrl> urls) {
+  public void setUrls(String urls) {
     this.urls = urls;
   }
 

app/src/main/java/chat/rocket/android/model/ddp/MessageUrl.java

-package chat.rocket.android.model.ddp;
-
-import io.realm.RealmObject;
-import io.realm.annotations.PrimaryKey;
-
-/**
- * Url.
- */
-@SuppressWarnings({"PMD.ShortClassName", "PMD.ShortVariable",
-    "PMD.MethodNamingConventions", "PMD.VariableNamingConventions"})
-public class MessageUrl extends RealmObject {
-  @PrimaryKey private String url;
-  private String parsedUrl;
-}