Yeah! So the way we got it to work was to add the build script to package.json and run our locally-installed gulp command (which gets installed from devDependencies) from there. So in our package.json it looks something like this:
"scripts": {
"build": "./node_modules/.bin/gulp"
},
"devDependencies": {
"gulp": "^3.9.1"
}
Notice the ./node_modules/.bin part, that is how we run gulp installed with our package