Improve Guardfile:

* Prevent cucumber run on start;
* Force rspec to be executed by bundler.

Guardfile

@@ -1,10 +1,10 @@
-guard :cucumber, cli: '--format pretty --quiet' do
+guard :cucumber, cli: '--format pretty --quiet', all_on_start: false do
   watch(%r{\Afeatures/.+\.feature\z})
   watch(%r{\Afeatures/support/.+\.rb\z})                { 'features' }
   watch(%r{\Afeatures/step_definitions/.+_steps\.rb\z}) { 'features' }
 end
 
-guard :rspec, cmd: 'rspec -f doc' do
+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' }