gulpfile.js

var gulp = require('gulp'),
	sass = require('gulp-sass'),
	uglify = require('gulp-uglifyjs'),
	concat = require('gulp-concat'),
	autoprefixer = require('gulp-autoprefixer');

gulp.task('sass', function () {
	return gulp.src('dist/sass/**/*.scss')
	.pipe(sass({outputStyle: 'compressed'}).on('error', sass.logError))
		.pipe(autoprefixer({
			browsers: ['last 20 versions'],
			cascade: false
		}))
		.pipe(gulp.dest('app/css/'));
});

gulp.task('scripts', function() {
 return gulp.src([
	'dist/js/*.js'
	])
	.pipe(concat('libs.min.js'))
	.pipe(uglify())
	.pipe(gulp.dest('app/js'));
});

gulp.task('watch', ['sass', 'scripts'], function(){
	gulp.watch('dist/sass/**/*.scss', ['sass']);
	gulp.watch('dist/js/*.js', ['scripts']);
});

gulp.task('default', ['watch']);