Gulpfile.js

var gulp = require('gulp');
var sass = require('gulp-sass');
var concat = require('gulp-concat');

gulp.task('styles', function() {
  gulp.src('styles/**/*.scss')
    .pipe(sass({
        errLogToConsole: true
    }))
    .pipe(gulp.dest('./public/stylesheets/'))
    .pipe(concat('style.css'));
});