Config Grunt

grunt-config.js

{
    "watch": {
        "options": {
            "livereload": true
        },
        "css": {
            "files": "app/styles/**/*.styl",
            "tasks": ["stylus"]
        },
        "js": {
            "files": "<%= jshint.all %>",
            "tasks": ["jshint", "uglify"]
        },
        "html": {
            "files": [ "/*.{html,htm,shtml,shtm,xhtml,php,jsp,asp,aspx,erb,ctp}" ]
        }
    },
    "browserSync": {
        "dev": {
            "bsFiles": {
                "src" : "public/css/*.css"
            },
            "options": {
                "watchTask": true,
                "server": {
                    "baseDir": "./",
                    "index": "index.html"
                }
            }
        }
    },
    "jshint": {
        "options": {
            "jshintrc": ".jshintrc"
        },
        "all": [ "Gruntfile.js", "public/js/main.js" ]
    },
    "uglify": {
        "options": {
            "mangle": false
        },
        "build": {
            "files": {
                "js/main.min.js": [
                "js/main.js"
                ]
            }
        }
    },
    "stylus": {
        "options": {
            "compress": false
        },
        "files": {
            "src":  "app/styles/style.styl",
            "dest": "public/styles/style.css"
        }
    }
}

Gruntfile.js

module.exports = function(grunt) {

    'use strict';

     // Carrega os plugins relacionados no package.json
    //require('time-grunt')(grunt);
    require('load-grunt-tasks')(grunt);

    // Utilizamos o método grunt.file para fazer o parse do grunt-config.json
    var gruntConfig = grunt.file.readJSON('./grunt-config.json');
    grunt.initConfig(gruntConfig);

    //Build Projetc
    grunt.registerTask('build', ['stylus']);

    // Registra a tarefa padrão
    grunt.registerTask('default', ['stylus', 'browserSync', 'watch']);
};