message: build error fix (reverting backend to es5)
diff: @@ -5,7 +5,7 @@ var runSequence = require('run-sequence');
  var jsonModify = require('gulp-json-modify');
  var exec = require('child_process').exec;
  -var tsBackendProject = ts.createProject('backend/tsconfig.json');
  +var tsBackendProject = ts.createProject('tsconfig.json');
  gulp.task('build-backend', function () {
  return gulp.src([
  "common/**/*.ts",
  