docs: Add vuepress.tools to the readme showcase section (#2143)

Author: z3by

README.md

@@ -30,6 +30,7 @@ yarn add vuepress -D
 
 - [Awesome VuePress](https://github.com/ulivz/awesome-vuepress)
 - [vuepress.gallery](https://vuepress.gallery) (by [@vicbergquist](https://twitter.com/vicbergquist))
+- [vuepress.tools](https://vuepress.tools/) (By [Ahmad Mostafa](https://ahmadmostafa.com))
 
 ## Documentation