a few changes to make A/B testing easier

build/package_json_loader.js

@@ -0,0 +1,11 @@
+const commit = require('git-rev-sync').short();
+
+module.exports = function(source) {
+  const pkg = JSON.parse(source);
+  const version = {
+    commit,
+    source: pkg.homepage,
+    version: process.env.CIRCLE_TAG || `v${pkg.version}`
+  };
+  return `module.exports = '${JSON.stringify(version)}'`;
+};