Update gitignore (sorry)

electron/node_modules/node-gyp/lib/clean.js

@@ -0,0 +1,15 @@
+'use strict'
+
+const rm = require('rimraf')
+const log = require('npmlog')
+
+function clean (gyp, argv, callback) {
+  // Remove the 'build' dir
+  var buildDir = 'build'
+
+  log.verbose('clean', 'removing "%s" directory', buildDir)
+  rm(buildDir, callback)
+}
+
+module.exports = clean
+module.exports.usage = 'Removes any generated build files and the "out" dir'