Add Hanami support

[matsimitsu]

We've had a few customers ask about supporting Hanami (http://hanamirb.org/)

Support Hanami 2.0. It's now available as release candidate 1.

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⚠️ Old issue content from 2016-2017:

Hanami Controller

Hanami is split out in a few different projects, one of them is Hanami-Controller, it has a section about error handling: https://github.com/hanami/controller#exceptions-management

It looks like it does error handling on its own:
https://github.com/hanami/controller/blob/master/lib/hanami/controller/configuration.rb#L113

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@tombruijn: Since we received PR #322 we need to look at what steps we need to take to merge this in

TODO

• Review if the approach in PR Hanami support #322 with middleware is the best approach (0.5 days)
• Rewrite tests (0.5-0.75 days)
  • Use transaction.to_hsee PR Hanami support #322 for detailed description of rewrite needed
  • Convert from unit testing to more integration testing than just unit testing (by which I mean, do not just unit test the middleware, but unit test it through/with a real Hanami app. Something which I improved in our Grape integration specs recently.)
• Add Hanami integration documentation (0.25-0.5 days)
• Set up an example app on https://github.com/appsignal/appsignal-examples (0.5-0.75 days)
  • Test basic single app integration
  • Test multi app integration
  • Test other edge cases described in documentation
    • For example: namespaces (as these were a problem to support in Grape Support namespaces in Grape #189 )

[raytalks]

https://app.intercom.io/a/apps/yzor8gyw/inbox/conversation/8396790008%3Fnsrc=slack

[tombruijn]

Updated the issue description with a TODO list of steps we need to take to support Hanami fully.

[jeffkreeftmeijer]

https://app.intercom.io/a/apps/yzor8gyw/respond/inbox/unassigned/conversations/13531223939

[gotar]

New hanami will use ROM (Ruby Object Mapper) Will be good to have out of box support for it too (rom-sql use Sequel below, so maybe this will be helpful)

[tombruijn]

https://app.intercom.com/a/inbox/yzor8gyw/inbox/admin/4356044/conversation/16410700129981?view=List

[backlog-helper]

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[luismiramirez]

Hanami v2 is now supported in AppSignal for Ruby gem 3.3.0 (https://rubygems.org/gems/appsignal/versions/3.3.0)

Follow instructions here: https://docs.appsignal.com/ruby/integrations/hanami.html