Gulp file for Jekyll, Sass, Autoprefixer and BrowserSync

gulpfile.js

var gulp        = require('gulp');
var browserSync = require('browser-sync');
var sass        = require('gulp-sass');
var prefix      = require('gulp-autoprefixer');
var cp          = require('child_process');

var messages = {
    jekyllBuild: '<span style="color: grey">Running:</span> $ jekyll build'
};

gulp.task('sass', function () {
    return gulp.src('_scss/main.scss')
        .pipe(sass({
            includePaths: ['scss'],
            onError: browserSync.notify
        }))
        .pipe(prefix(['last 15 versions', '> 1%', 'ie 8'], { cascade: true }))
        .pipe(gulp.dest('assets/css'))
        .pipe(browserSync.reload({stream:true}))
        .pipe(gulp.dest('_site/assets/css'));
});

gulp.task('jekyll-build', function (done) {
    browserSync.notify(messages.jekyllBuild);
    return cp.spawn('jekyll', ['build'], {stdio: 'inherit'})
        .on('close', done);
});

gulp.task('jekyll-rebuild', ['jekyll-build'], function () {
    browserSync.reload();
});

gulp.task('browser-sync', ['sass', 'jekyll-build'], function() {
    browserSync({
        server: {
            baseDir: '_site'
        }
    });
});

gulp.task('watch', function () {
    gulp.watch('_scss/*.scss', ['sass']);
    gulp.watch(['**/*', '!_site/**', '!node_modules/**'], ['jekyll-rebuild']);
});

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

package.json

{
  "name": "username.github.io",
  "version": "1.0.0",
  "description": "",
  "main": "gulpfile.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "User",
  "license": "ISC",
  "devDependencies": {
    "gulp": "^3.8.8",
    "gulp-sass": "^0.7.3",
    "browser-sync": "^1.3.7",
    "gulp-autoprefixer": "^1.0.0"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/username/username.github.io.git"
  },
  "keywords": [
    "jekyll",
    "gulp",
    "sass",
    "browsersync"
  ],
  "bugs": {
    "url": "https://github.com/username/username.github.io/issues"
  },
  "homepage": "https://github.com/username/username.github.io"
}