Add package.json

In Node.js, to start a projet, try `npm init`. It will guide you and create a `package.json` file.
Each time you add a dependency (like Q), do it via `npm install q --save`. This will save the dependency and its version to the package.json file.
When someone clone your repo, they only need to do `npm install` and it installs the right things (especially right package versions).

Happy to answer any question if I was too quick in my explanation.