Providing a Rails template

The application_template.rb is included so others can reference the
template via `rails new my_curate \
-m https://raw.github.com/ndlib/curate/master/lib/generators/curate/application_template.rb`

The application_template.rb.erb is to be part of the release process;
Its purpose is to update the version number that application_template
applies to the Rails application that is built via the template.

@TODO - Update the rake task to commit changed template before pushing
the released Gem
Ref ndlib/planning#302