win7 环境下按照步骤来，npm install， bower install ，grunt serve 走不通

[heboliufengjie]

$ grunt serve
Running "serve" task

Running "clean:server" (clean) task

Running "bowerInstall:app" (bowerInstall) task
Cannot find where you keep your Bower packages.

We tried looking for a .bowerrc file, but couldn't find a custom
directory property defined. We then tried bower_components, but
it looks like that doesn't exist either. As a last resort, we tried
the pre-1.0 components directory, but that also couldn't be found.

Unfortunately, we can't proceed without knowing where the Bower
packages you have installed are.

Fatal error: No Bower components found.

Execution Time (2016-12-13 08:11:43 UTC)
loading tasks 4ms ■■■■■■■■■■ 21%
serve 2ms ■■■■■ 11%
clean:server 4ms ■■■■■■■■■■ 21%
bowerInstall:app 8ms ■■■■■■■■■■■■■■■■■■■ 42%
Total 19ms