Disallow additional properties in links schema of fixtures
Inject available_translations into links hash

.. when generating frontend schema.

Also explicitly test the scenario where the publisher schema may not
have had any links. In that scenario the frontend schema also needs to
insert some schema boilerplate for the links.
Frontend links definition should define array

Each frontend link is an array of items, so define this as a plural.
Specify that a frontend links definition gets injected
validation script
definition of `frontend_links` should be array
Makefile to validate all frontend examples

this relies on tweaking the validation script to guess which schema to use.
Rakefile which invokes rspec and then make
Add .ruby-version