Add production dependencies

node_modules/gulp-uglify/lib/gulp-uglify-error.js

@@ -0,0 +1,16 @@
+'use strict';
+var makeErrorCause = require('make-error-cause');
+
+var gulpUglifyError = makeErrorCause('GulpUglifyError');
+gulpUglifyError.prototype.toString = function() {
+  var cause = this.cause || {};
+
+  return (
+    makeErrorCause.BaseError.prototype.toString.call(this) +
+    (this.fileName ? '\nFile: ' + this.fileName : '') +
+    (cause.line ? '\nLine: ' + cause.line : '') +
+    (cause.col ? '\nCol: ' + cause.col : '')
+  );
+};
+
+module.exports = gulpUglifyError;