add animate-spin class

src/App.scss

@@ -855,3 +855,18 @@ nav {
 .btn.btn-default {
   min-height: 28px;
 }
+
+.animate-spin {
+  animation: spin 2s infinite linear;
+  display: inline-block;
+}
+
+@keyframes spin {
+  0% {
+    transform: rotate(0deg);
+  }
+
+  100% {
+    transform: rotate(359deg);
+  }
+}