add missing jQuery plugin scrollable fallback

Author: lazabogdan

src/js/scrollable.js

@@ -1,8 +1,9 @@
-import 'simplebar/src/simplebar'
+import 'simplebar/src/simplebar.js'
 
 export default function () {
 
 	$.fn.blScrollable = function () {
+
 		if (!this.length) return
 		if (this.length > 1) {
 			this.each(function () {
@@ -18,6 +19,11 @@ export default function () {
 			el.addClass('horizontal')
 		}
 
+		if ($.fn.simplebar === undefined) {
+			el.css('overflow-y', 'scroll')
+			return
+		}
+
 		el.simplebar()
 		el.simplebar().on('scroll', function () {
 			var scrollable = $(this)