Use Marshall to deep_copy template_config

[herebebogans]

Should fix #38.

[starchx]

@herebebogans Hi, can we create a release for this fix?

[herebebogans]

@starchx waiting for @ampedandwired to review.

Do you want to try using my fork in a bundle to test the fix?

Try a gemfile like the following in your project

source 'https://rubygems.org'

gem 'bora', git: 'https://github.com/herebebogans/bora.git', branch: 'fix_deep_merge'

then bundle exec bora <command> will use it.