update glitch link to point at directory version of starter kit

Author: Ben Brown

readme.md

@@ -31,7 +31,7 @@ While Botkit Studio is *not required* to build a bot using Botkit, we highly rec
 
 #### Install Botkit
 
-[Remix this project on Glitch](https://glitch.com/edit/#!/import/github/howdyai/botkit-starter-slack)
+[Remix this project on Glitch](https://glitch.com/~botkit-slack)
 
 [Deploy to Heroku](https://heroku.com/deploy?template=https://github.com/howdyai/botkit-starter-slack/master)