IDEX-3128: Add posibility to get mirror repository url.

Will be used for warn user if the try contribute mirrored repository like https://github.com/apache/tomee.
Also create pull request to original lib hub4j/github-api#233

plugin-github/che-plugin-github-ext-github/src/main/java/org/eclipse/che/ide/ext/github/server/rest/GitHubService.java

@@ -35,6 +35,7 @@
 import org.kohsuke.github.GHRepository;
 import org.kohsuke.github.GitHub;
 
+import org.kohsuke.github.IsMirrorRepo;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -82,7 +83,12 @@ public class GitHubService {
     public GitHubRepository getUserRepository(@PathParam("user") String user, @PathParam("repository") String repository)
             throws ApiException {
         try {
-            return gitHubDTOFactory.createRepository(gitHubFactory.connect().getUser(user).getRepository(repository));
+            final GitHub gitHub = gitHubFactory.connect();
+            final GitHubRepository gitHubRepository = gitHubDTOFactory.createRepository(gitHub.getUser(user).getRepository(repository));
+            gitHubRepository.setMirrorUrl(IsMirrorRepo.getMirrorUrl(gitHub, user, repository));//For now we need this hack it because original API
+                                                                                               //don't parse mirror url. Pull request to GitHub API
+                                                                                               //https://github.com/kohsuke/github-api/pull/233
+            return gitHubRepository;
         } catch (IOException e) {
             LOG.error("Get user info error", e);
             throw new ServerException(e.getMessage());

plugin-github/che-plugin-github-ext-github/src/main/java/org/eclipse/che/ide/ext/github/shared/GitHubRepository.java

@@ -19,6 +19,15 @@
  */
 @DTO
 public interface GitHubRepository {
+
+    /**
+     *
+     * @return  mirror url if it mirrored repository like http://github.com/apache/tomee
+     */
+    String getMirrorUrl();
+
+    void setMirrorUrl(String mirrorUrl);
+
     /**
      * Get repository's name.
      *

plugin-github/che-plugin-github-ext-github/src/main/java/org/kohsuke/github/GHRepositoryWithMirrorUrl.java

@@ -0,0 +1,28 @@
+/*******************************************************************************
+ * Copyright (c) 2012-2015 Codenvy, S.A.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   Codenvy, S.A. - initial API and implementation
+ *******************************************************************************/
+package org.kohsuke.github;
+
+/**
+ * Add mirror url original lib don't support it
+ *
+ * @author Vitalii Parfonov
+ */
+@SuppressWarnings({"UnusedDeclaration"})
+public class GHRepositoryWithMirrorUrl extends GHRepository {
+
+
+    private String mirror_url;
+
+
+    public String getMirrorUrl() {
+        return mirror_url;
+    }
+}

plugin-github/che-plugin-github-ext-github/src/main/java/org/kohsuke/github/IsMirrorRepo.java

@@ -0,0 +1,25 @@
+/*******************************************************************************
+ * Copyright (c) 2012-2015 Codenvy, S.A.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *   Codenvy, S.A. - initial API and implementation
+ *******************************************************************************/
+package org.kohsuke.github;
+
+import java.io.IOException;
+
+/**
+ * Return mirror url if it exist otherwise null
+ *
+ * @author Vitalii Parfonov
+ */
+public class IsMirrorRepo {
+
+    public static String getMirrorUrl(GitHub gitHub, String user, String repo) throws IOException {
+        return gitHub.retrieve().to("/repos/" + user + '/' + repo, GHRepositoryWithMirrorUrl.class).getMirrorUrl();
+    }
+}