I've tried to find some solution for this, but I really couldn't find anything related with the errors that is appearing to me when I run the rails command:
rails generate model Book title:string summary:text isbn:string
/home/vmu/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:51: warning: constant ::Fixnum is deprecated
/home/vmu/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-5.0.1/lib/active_support/xml_mini.rb:52: warning: constant ::Bignum is deprecated
/home/vmu/.rbenv/versions/2.4.0/lib/ruby/gems/2.4.0/gems/activesupport-5.0.1/lib/active_support/core_ext/numeric/conversions.rb:138: warning: constant ::Fixnum is deprecated
Running via Spring preloader in process 3579
Expected string default value for '--jbuilder'; got true (boolean)
invoke active_record
identical db/migrate/20170104114702_create_books.rb
identical app/models/book.rb
invoke test_unit
identical test/models/book_test.rb
identical test/fixtures/books.yml
Anyone know what may be causing these errors?
This warnings appear because you are using ruby 2.4.0.
This version introduced this change: Unify Fixnum and Bignum into Integer
See here for the announcement: https://www.ruby-lang.org/en/news/2016/12/25/ruby-2-4-0-released/
The warnings come from the activesupport gem which is part of rails and will be fixed in an upcoming release.
For now you can just ignore those warnings.
Update: Rails 5.0.2 has been released, which gets rid of the warnings.