Steps to upgrade to Ruby 3.0

Upgrade to Ruby 3.0

STEP1: ruby 2.6 to 2.7 challenges
1. installed latest through rvm version
2. gem install bundler
3. just change puma version in gemfile to latest, it resolved
output: lots of warning errors coming from active record for **argument errors on running console or something

STEP2: after that updated the rails version to 6.0.4.4 (because rails 6.0.4 handled errors and warning from ruby 2.7)
update rails version in gemfile, and then run bundle update
it took a lot of time to update bundle
OUTPUT: on rails console, warning are gone. fetched user from console, worked cool

STEP3: try to up upgrade to ruby 3.0.0
1. error raised as rvm couldnt find ruby, have to install latest stable rvm version => rvm get stable
2. rvm reload
3. rvm install ruby-3.0.0
4. gem rspec-rubocop creating issue to require rainbow gem - /Users/simran/.rvm/gems/ruby-3.0.0/gems/activesupport-6.0.4.4/lib/active_support/dependencies.rb:324:in `require': cannot load such file -- rainbow (LoadError)
5. Rails param needs code change everywhere as rails param new version changed exception handling class name. https://github.com/nicolasblanco/rails_param/blob/master/UPGRADING.md
6. wherever ** arguments were expected and for example you have sent a hash foo({a: 1}), change it to rather foo(a: 1),, def foo (**args); end;
7. update .ruby-version file
8. update gemfile to mention correct ruby version 3.0.0