remove explicit require for thread_safe

[ritikesh]

In Rails master, tzinfo has been updated to 2.x, which no longer depends on the thread_safe gem and has moved to concurrent-ruby instead. Thereby, unless you're explicitly adding thread_safe to your Gemfile, active_model_serializers throws up a cannot require thread_safe. #2369 has already replaced ThreadSafe::Cache with Concurrent::Map. This require should no longer be required!(😅 )

[bf4]

Looks good. Wanna help fix CI, too?

/home/travis/build/rails-api/active_model_serializers/vendor/bundle/ruby/2.2.0/gems/pry-byebug-3.6.0/lib/pry-byebug/commands/exit_all.rb:5:in `<module:PryByebug>': uninitialized constant Pry::Command::ExitAll (NameError)
	from /home/travis/build/rails-api/active_model_serializers/vendor/bundle/ruby/2.2.0/gems/pry-byebug-3.6.0/lib/pry-byebug/commands/exit_all.rb:1:in `<top (required)>'

[ritikesh]

Hi @bf4, thanks for responding. Have tried fixing by removing the redundant gem itself. I believe pry & byebug gems should be more than enough.

[ritikesh]

Hi @bf4 - looks like the CI is still failing on this, but don't think it's related to my changes.

[bf4]

@ritikesh probably not related to your changes. I was just wondering if you could help fix it :)

[connorshea]

This is causing problems for upgrading to Rails 6.1 (see above rails issue), could we get a new release with this fix?

[ritikesh]

#2398