dotenv is not installed

The project uses a .env file to read the GITHUB_TOKEN. But it doesn't have the package dotenv in package.json, and its missing this line in gatsby-config.js: require('dotenv').config();

I've made a pull request here: #239

Addressed by #266: GITHUB_TOKEN can now come from a git-ignored .env file, read with Node's built-in loader (no dotenv dependency), and the README documents it. Closing now, with #266 pending merge.