title: Unable to get gulp autoprefixer working
body: <p>I'm currently setting up a new project with gulp and I cannot get gulp-autoprefixer to work. </p>
  
  <p>Below is my gulpfile.js so far.</p>
  
  <pre><code>var gulp = require('gulp'),
      sass = require('gulp-sass'),
      prefix = require('gulp-autoprefixer'),
      rename = require('gulp-rename'),
      livereload = require('gulp-livereload'),
      sourcemaps = require('gulp-sourcemaps');
  
  gulp.task('styles', function() {
    gulp.src('css/**/*.scss')
      .pipe(sourcemaps.init())
      .pipe(prefix('last 2 version'))
      .pipe(sass().on('error', sass.logError))
      .pipe(sourcemaps.write('./'))
      .pipe(rename({suffix: '.min'}))
      .pipe(gulp.dest('./css/'));
  });
  
  gulp.task('default',function() {
    gulp.watch('css/**/*.scss',['styles']);
    livereload.listen();
    gulp.watch(['./**/*']).on('change', livereload.changed);
  });
  </code></pre>