Update Readme.md

Readme.md

@@ -4,5 +4,5 @@ So far, we wrote a hello world Dream server.
 
 ## How to setup
 
-1. Install `esy` with `npm i -g esy`
+1. Install nightly build of `esy` with `npm i -g @esy-nightly/esy`
 2. Run `esy` inside the project