Update README.md

Author: tsv2013

README.md

@@ -24,6 +24,10 @@
 
   - easyautocomplete: [site](http://easyautocomplete.com/), [repo](https://github.com/pawelczak/EasyAutocomplete), license: https://github.com/pawelczak/EasyAutocomplete/blob/master/LICENSE.txt
 
+  - pretty-checkbox: [site](https://lokesh-coder.github.io/pretty-checkbox/), [repo](https://github.com/lokesh-coder/pretty-checkbox/), license: https://github.com/lokesh-coder/pretty-checkbox/blob/master/LICENSE
+  
+  - bootstrap-slider: [site](http://seiyria.com/bootstrap-slider/), [repo](https://github.com/seiyria/bootstrap-slider), license: https://github.com/seiyria/bootstrap-slider/blob/master/LICENSE.md
+  
   ## Getting started
 es5 examples: https://surveyjs.io/Examples/Library/?id=custom-widget-select2-tagbox  
 es moules examples: https://stackblitz.com/edit/surveyjs-widgets-react