Migrating from Gruntfile.js to gulpfile.js

I am trying to use the tool grunt2gulp.js to migrate multiple projects that were set up with grunt into gulp. However, I am unsure how to proceed.

The tool grunt2gulp.js seems to be a simple way to start, but the problem I am having is that I cannot get it to work. As there is no npm install -g grunt2gulp, I am somewhat unsure what I need to do to install the project globally and be able to access it.

The readme.md on the github repo doesn't specify how to install the project.