guard-hydra/lib/guard/hydra/templates/Guardfile

guard 'hydra' do
  # All spec files
  watch(%r{^spec/**/*_spec.rb$})

  # All lib files
  watch(%r{^lib/(.*)\.rb$}) { |m| "spec/lib/#{m[1]}_spec.rb" }

  # All app files for a Rails app
  watch(%r{^app/(.*)\.rb$}) { |m| "spec/#{m[1]}_spec.rb" }
end