Try to load SCM-Manager after migration

scm-webapp/src/main/resources/templates/repository-migration-restart.mustache

@@ -24,9 +24,69 @@
             <h1 class="title">SCM-Manager will restart to migrate the data.</h1>
           </div>
         </section>
+        <section class="section">
+          <p class="has-text-centered">
+            <!--          <img src="{{ contextPath }}/images/loading.png" alt="Loading...">-->
+            <svg width="200px" version="1.1" id="L7" xmlns="http://www.w3.org/2000/svg"
+                 xmlns:xlink="http://www.w3.org/1999/xlink"
+                 x="0px" y="0px"
+                 viewBox="0 0 100 100" enable-background="new 0 0 100 100" xml:space="preserve">
+       <path fill="#33B2E8" d="M31.6,3.5C5.9,13.6-6.6,42.7,3.5,68.4c10.1,25.7,39.2,38.3,64.9,28.1l-3.1-7.9c-21.3,8.4-45.4-2-53.8-23.3
+        c-8.4-21.3,2-45.4,23.3-53.8L31.6,3.5z">
+            <animateTransform
+              attributeName="transform"
+              attributeType="XML"
+              type="rotate"
+              dur="2s"
+              from="0 50 50"
+              to="360 50 50"
+              repeatCount="indefinite"/>
+        </path>
+              <path fill="#33B2E8" d="M42.3,39.6c5.7-4.3,13.9-3.1,18.1,2.7c4.3,5.7,3.1,13.9-2.7,18.1l4.1,5.5c8.8-6.5,10.6-19,4.1-27.7
+        c-6.5-8.8-19-10.6-27.7-4.1L42.3,39.6z">
+            <animateTransform
+              attributeName="transform"
+              attributeType="XML"
+              type="rotate"
+              dur="1s"
+              from="0 50 50"
+              to="-360 50 50"
+              repeatCount="indefinite"/>
+        </path>
+              <path fill="#33B2E8" d="M82,35.7C74.1,18,53.4,10.1,35.7,18S10.1,46.6,18,64.3l7.6-3.4c-6-13.5,0-29.3,13.5-35.3s29.3,0,35.3,13.5
+        L82,35.7z">
+            <animateTransform
+              attributeName="transform"
+              attributeType="XML"
+              type="rotate"
+              dur="2s"
+              from="0 50 50"
+              to="360 50 50"
+              repeatCount="indefinite"/>
+        </path>
+      </svg>
+          </p>
+        </section>
       </div>
     </div>
   </div>
 </div>
+<script>
+  setInterval(function () {
+      const request = new XMLHttpRequest();
+
+      request.open('GET', '{{ contextPath }}/api/v2/', true);
+
+      request.onload = function () {
+        if (this.readyState == 4 && this.status == 200 && this.response.toString().indexOf("_links") > 0) {
+          location.href = '{{ contextPath }}';
+        }
+      };
+
+      request.send();
+    },
+    3000
+  );
+</script>
 </body>
 </html>