Simple `chef update` Command

Adds a basic `chef update` command that updates the lockfile with any changes to the `Policyfile.rb` and fetches the latest matching cookbooks.

@opscode/client-engineers 
Fair enough

On Sat Dec 06 2014 at 10:35:19 AM Dan DeLeo <notifications@github.com>
wrote:

> In spec/unit/policyfile_services/install_spec.rb:
>
> > @@ -111,6 +113,23 @@ def result_policyfile_lock
> >
> >      end
> >
> > +    context "and a lockfile exists and `overwrite` is specified" do
> > +
> > +      let(:overwrite) { true }
> > +
> > +      before do
> > +        File.open(policyfile_lock_path, "wb+") { |f| f.puts("This is the old lockfile content") }
>
> I don't like to use production code like that in tests, but it could be
> implemented in the test helpers.
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/opscode/chef-dk/pull/262/files#r21418213>.
>