`serve` command try to watch node_modules

[dekelyi]

the serve command try to watch all the files in the serving directory, including the node_modules, what results in ENOSPC error on linux when trying to watch too many files.
Source for the bug: jestjs/jest#3254

exclude the node_modules directory when watching files.

[chikamichi]

Hi,

This is a problem indeed. It prevents from running docsify in many container-based platform, for instance.

[jonoirwinrsa]

seems like there is a small attempt to try and ignore those files:
https://github.com/docsifyjs/docsify-cli/blob/master/lib/commands/serve.js#L56

I am wondering where it is going wrong

[dekelyi]

I'm not sure how the API works, but maybe changing it to **/node_modules/ will work