(js) Add sg-category-stylesheet directive

Fixes #3816

UI/Templates/SchedulerUI/UIxCalMainView.wox

@@ -27,7 +27,7 @@
     <sg-folder-stylesheet
          ng-repeat="calendar in app.service.$findAll()"
          ng-model="calendar"><!-- stylesheet --></sg-folder-stylesheet>
-    <!-- calendars colors -->
+    <!-- categories colors -->
     <sg-category-stylesheet
          ng-repeat="category in app.categories"
          ng-model="category"><!-- stylesheet --></sg-category-stylesheet>

UI/WebServerResources/js/Scheduler/sgCategoryStylesheet.directive.js

@@ -0,0 +1,44 @@
+/* -*- Mode: javascript; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+
+(function() {
+  /* jshint validthis: true */
+  'use strict';
+
+  /*
+   * sgCategoryStylesheet - Add CSS stylesheet for a category's color
+   * @memberof SOGo.SchedulerUI
+   * @restrict attribute
+   * @param {object} ngModel - the object literal describing the category
+   * @example:
+
+    <sg-category-stylesheet
+         ng-repeat="category in categories"
+         ng-model="category" />
+  */
+  function sgCategoryStylesheet() {
+    return {
+      restrict: 'E',
+      require: 'ngModel',
+      scope: {
+        ngModel: '='
+      },
+      replace: true,
+      template: [
+        '<style type="text/css">',
+        /* Background color */
+        '  .bg-category{{ ngModel.id }} {',
+        '    background-color: {{ ngModel.color }} !important;',
+        '  }',
+        /* Border color */
+        '  .bdr-category{{ ngModel.id }} {',
+        '    border-color: {{ ngModel.color }} !important;',
+        '  }',
+        '</style>'
+      ].join('')
+    };
+  }
+
+  angular
+    .module('SOGo.SchedulerUI')
+    .directive('sgCategoryStylesheet', sgCategoryStylesheet);
+})();