Finish select2-ajax for users. Added Select2Helper for tests

app/assets/stylesheets/selects.scss

@@ -0,0 +1,110 @@
+.ajax-users-select {
+  width: 400px;
+}
+
+.user-result {
+  .user-image {
+    float: left;
+  }
+  .user-name {
+  }
+  .user-username {
+    color: #999;
+  }
+}
+
+.select2-no-results {
+  padding: 7px;
+  color: #666;
+}
+
+/** Branch/tag selector **/
+.project-refs-form {
+  margin: 0;
+  span {
+    background:none !important;
+    position:static !important;
+    width:auto !important;
+    height:auto !important;
+  }
+}
+.project-refs-select {
+  width: 120px;
+}
+
+.project-refs-form .chzn-container {
+  position: relative;
+  top: 0;
+  left: 0;
+  margin-right: 10px;
+
+  .chzn-drop {
+    min-width: 400px;
+    .chzn-results {
+      max-height: 300px;
+    }
+    .chzn-search input {
+      min-width: 365px;
+    }
+  }
+}
+
+/** Fix for Search Dropdown Border **/
+.chzn-container {
+  .chzn-search {
+    input:focus {
+      @include box-shadow(none);
+    }
+  }
+
+  .chzn-drop {
+    margin: 7px 0;
+    min-width: 200px;
+    border: 1px solid #bbb;
+    @include border-radius(0);
+
+    .chzn-results {
+      margin-top: 5px;
+      max-height: 300px;
+
+      .group-result {
+        color: $style_color;
+        border-bottom: 1px solid #EEE;
+        padding: 8px;
+      }
+      .active-result {
+        @include border-radius(0);
+
+        &.highlighted {
+          background: $hover;
+          color: $style_color;
+        }
+        &.result-selected {
+          background: #EEE;
+          border-left: 4px solid #CCC;
+        }
+      }
+    }
+
+    .chzn-search {
+      @include bg-gray-gradient;
+      input {
+        min-width: 165px;
+        border-color: #CCC;
+      }
+    }
+  }
+
+  .chzn-single {
+    @include bg-light-gray-gradient;
+
+    div {
+      background: transparent;
+      border-left: none;
+    }
+
+    span {
+      font-weight: normal;
+    }
+  }
+}