Add Grunt task to make sure uploads directory exists

[simison]

Using Grunt's internal mkdir().

It creates the folder only if it doesn't exist already.

Alternative solution for #584

[ilanbiala]

@lirantal LGTY?

[lirantal]

We just need one more thing before we merge - please add that uploads directory /modules/users/client/img/profile/uploads to .gitignore so that users don't accidentally push binary data to repositories/PRs.

Other than that looks good, thanks @simison

[simison]

@lirantal it's there already: https://github.com/meanjs/mean/blob/0.4.0/.gitignore#L23

I was a bit confused about ./uploads/ directory appearing there as well, but that comes from some multipart middleware stuff. That "uploads" is in .gitignore as well, so it effectively ignores any "uploads" directory/file anywhere at the folder structure. Making that "uploads/" instead would fix it but this is a bit of bikeshedding already...

[lirantal]

Great, so we're good here.