Update installation instructions

Author: th-awake

updater/README.md

@@ -12,6 +12,12 @@ The Nix shell provides all necessary dependencies and hooks for installing depen
 nix-shell
 ```
 
+This will produce an `bin/index.js` file, which is the executable script. You can run commands using the path to this script. The easiest way to do so is by aliasing the full path:
+
+```sh
+alias contrib-updater='node ~/path/to/governance/updater/bin/index.js'
+```
+
 You can now use `contrib-updater` to run the tool:
 
 ```sh

updater/shell.nix

@@ -24,6 +24,5 @@ in pkgs.stdenv.mkDerivation {
   shellHook =''
     npm install
     npm run build
-    alias contrib-updater='${pkgs.nodejs-12_x}/bin/node "./bin/index.js"'
   '' ;
 }