Change 'rb-inotify' version to 0.8.8 to avoid problems on Linux

See guard logs:
[Listen warning]:
  Missing dependency 'rb-inotify' (version '~> 0.8.8')!
  Please add the following to your Gemfile to satisfy the dependency:
    gem 'rb-inotify', '~> 0.8.8'
Show syntax errors connected with JSON files (interactive, model)

[#43484231]