I have just installed Rails in its version 5.1 and when creating a new project and run the command bundle install me the following message.
The dependency tzinfo-data (> = 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java .
The message is harmless and you can ignore it; in fact it is shown because you are probably not using windows, however your Gemfile has the line as shown by Vicente in his answer (rails adds it by default):
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
The objective of this line is to include the gem tzinfo-data in windows, which is used to obtain information about time zones .
If you still want to delete the message, simply delete the platforms option:
gem 'tzinfo-data'
and execute bundle update .
Or, you can delete it completely, but consider that it will generate an error if you get to run your application in Windows.
in the Gemfile file of your app, look to see if where you have it referenced something like this appears:
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]
If not, put it like this in case you are using windows