Update README.md

grunt -> gulp
Merge pull request #7 from lvwzhen/patch-1

Update README.md
更新项目说明
Merge branch 'master' of github.com:protoshop/protoshop-web

* 'master' of github.com:protoshop/protoshop-web:
  更新项目说明
  Update README.md
Merge branch 'master' into dev

* master:
  更新项目说明
  Update README.md