modify Rakefile to watch assets folder as well

[ashmaroli]

This pull modifies the Rakefile to have the assets dir watched during development

/cc @jekyll/minima

[benbalter]

Dumb question... why can't we just use jekyll serve --watch?

[ashmaroli]

why can't we just use jekyll serve --watch?

@benbalter, because:

• --watch is enabled by default for the source_dir (/example in this case) and not the theme_gem (minima) files.
• we watch minima files during development by having the Rakefile define what to watch.
  Hence bundle exec rake preview uses current minima-branch instead of an installed version.

[benbalter]

Can we simplify that by collapsing the example files into the root?

[ashmaroli]

Can we simplify that by collapsing the example files into the root?

I'm against that because I'd like the root to only show directories actually relevant to the theme. We can easily test n showcase Jekyll reading extra-source_dir directories n files. Hope that's clear..

But if the other members on @jekyll/minima are fine with the move, I wont mind..

[DirtyF]

@benbalter isn't what we've done in #76 ?

[benbalter]

I'd rather go with #76 here. Less code is more better. Thanks @ashmaroli, as always for the PR and sorry for the slow response.