userref asset out of date, updated code to v3 can't get app.js and css files to build in dist folder.

gulp.task('compileSass', function() {
  return gulp.src(options.src + "/scss/application.scss")
      .pipe(maps.init())
      .pipe(sass())
      .pipe(maps.write('./'))
      .pipe(gulp.dest(options.src + '/css'));
});
```javascript 





```javascript
'use strict';

const gulp = require('gulp'),
  concat = require('gulp-concat'),
  uglify = require('gulp-uglify'),
  rename = require('gulp-rename'),
  sass = require('gulp-sass'),
  maps = require('gulp-sourcemaps'),
  del = require('del'),
  useref = require('gulp-useref'),
  iff = require('gulp-if'),
  csso = require('gulp-csso');

  var options = {
    src: 'src',
    dist: 'dist'
  }

// gulp.task('concatScripts', function() {
//   return gulp.src([
//    'js/jquery.js',
//    'js/sticky/jquery.sticky.js',
//    'js/main.js'])
//   .pipe(maps.init())
//   .pipe(concat('app.js'))
//   .pipe(maps.write('./'))
//   .pipe(gulp.dest('js'));
// });

// gulp.task('minifyScripts',["concatScripts"], function(){
//   return gulp.src('js/app.js')
//   .pipe(uglify())
//   .pipe(rename('app.min.js'))
//   .pipe(gulp.dest('js'));
// });


gulp.task('compileSass', function() {
  return gulp.src(options.src + "/scss/application.scss")
      .pipe(maps.init())
      .pipe(sass())
      .pipe(maps.write('./'))
      .pipe(gulp.dest(options.src + '/css'));
});

gulp.task('watchFiles', function() {
  gulp.watch(options.src + '/scss/**/*.scss', ['compileSass']);
})

gulp.task('clean', function() {
  del([options.dist, options.src + '/css/application.css*']);
});

gulp.task('html', ['compileSass'], () => {
  return gulp.src('/src/index.html')
    .pipe(useref())
    .pipe(iff('*.js', uglify()))
    .pipe(iff('*.css', csso()))
    .pipe(gulp.dest(options.dist));
});



gulp.task("build", ['html'], function() {
  return gulp.src([options.src + "/img/**", options.src + "/fonts/**"], { base: options.src})
            .pipe(gulp.dest(options.dist));
});

gulp.task('serve', ['watchFiles']);

gulp.task("default", ["clean"], function() {
  gulp.start('build');
});

```javascript