Upgrade Rails from 6.1 to 7.0

[steveyken]

https://guides.rubyonrails.org/upgrading_ruby_on_rails.html#upgrading-from-rails-6-1-to-rails-7-0

Note particularly changes to:

• zeitwerk
• config.load_defaults 7.0

[steveyken]

@abulsayyad123 @swatijadhav @namrataukirde any interest for some Hacktoberfest PRs? :)

[steveyken]

@abulsayyad123 @swatijadhav @namrataukirde any interest for some Hacktoberfest PRs? :)