Configure guard for cucumber and rspec

Guardfile

@@ -0,0 +1,12 @@
+directories %w[features lib spec]
+
+guard :cucumber, cli: '--format pretty --quiet', all_on_start: false do
+  watch(%r{\Afeatures/.+\.feature\z})
+end
+
+guard :rspec, cmd: 'bundle exec rspec -f doc' do
+  watch(%r{\Aspec/.+_spec\.rb\z})
+  watch(%r{\Alib/(.+)\.rb\z})         { |m| "spec/#{m[1]}_spec.rb" }
+  watch('spec/spec_helper.rb')        { 'spec' }
+  watch(%r{\Aspec/support/.+\.rb\z})  { 'spec' }
+end