Carregue todas as tarefas grunhidas de uma só vez

Bom caminho:

npm install --save-dev matchdep

 require('matchdep'). 
filterDev('grunt-*'). 
forEach(grunt.loadNpmTasks); 

Melhor maneira

npm install --save-dev load-grunt-tasks

require('load-grunt-tasks')(grunt); //load all grunt tasks matching the `grunt-*` pattern