Basic PostCSS Gulpfile setup

Gulpfile.js

var gulp = require('gulp');
var rename = require('gulp-rename');
var postcss = require('gulp-postcss');

gulp.task('styles', function () {
  var processors = [
  ];
  return gulp.src('./*.postcss')
    .pipe(postcss(processors))
    .pipe(rename({
      extname: '.css'
    }))
    .pipe(gulp.dest('./'));
});