gistfile1.js

module.exports = function(grunt) {
	'use strict';
	require('load-grunt-tasks')(grunt);

	grunt.initConfig({
		sass: {
	        options: {
	            sourceMap: false
	        },
	        dist: {
	            files: {
	                'css/main.css' : '_scss/style.scss'
	            },
	        }
	    },
	    clean: {
			build: {
				src: ["css/"]
			}
		},
		watch: {
			css: {
				files: ['_scss/**', '_scss/*.scss'],
				// tasks: ['clean', 'sass']
				tasks: ['sass']
			}
		}
	});

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