Gruntfile.js with sass, postcss, concat, uglify, and watch

Gruntfile.js

module.exports = function(grunt) {
    grunt.initConfig({
        pkg: grunt.file.readJSON('package.json'),
        sass: {
            dist: {
                options: {
                    sourcemap: 'inline'
                },
                files: {
                    'dist/css/style.css' : 'src/scss/style.scss'
                }
            }
        },
        postcss: {
            options: {
                map: true, // inline sourcemaps
                processors: [
                    require('pixrem')(), // add fallbacks for rem units
                    require('autoprefixer')({browsers: 'last 2 versions'}), // add vendor prefixes
                    require('cssnano')() // minify the result
                ]
            },
            dist: {
                'dist/css/style.css'
            }
        },
        concat: {
            options: {
                separator: ';\n'
            },
            dist: {
                src: [
                    'src/js/script.js'
                ],
                dest: 'dist/js/script.concat.js'
            }
        },
        uglify: { // Begin JS Minify Plugin
            build: {
                src: 'dist/js/script.concat.js',
                dest: 'dist/js/script.min.js'
            }
        },
        watch: {
            grunt: {
                options: {
                reload: true
                },
                files: ['Gruntfile.js']
            },
            css: {
                files: ['src/scss/*.scss', 'src/scss/**/*.scss'],
                tasks: ['sass', 'postcss']
            },
            js: {
                files: ['src/js/*.js', 'src/js/**/*.js']
                tasks: ['concat, uglify']
            }
        }
    });
    grunt.loadNpmTasks('grunt-contrib-sass');
    grunt.loadNpmTasks('grunt-postcss');
    grunt.loadNpmTasks('grunt-contrib-concat');
    grunt.loadNpmTasks('grunt-contrib-uglify');
    grunt.loadNpmTasks('grunt-contrib-watch');

    grunt.registerTask('default', ['watch']);
}