Suppress request strategy log messages for every request

[Borzik]

Right now all requests are being wrapped with Chewy.strategy(Chewy.request_strategy) { @app.call(env) }. So every request will have two log entries for default Chewy.request_strategy added and removed from stack.
Here's what current log looks like:

Started GET "/articles" for 127.0.0.1 at 2017-07-22 20:25:44 +0300
DEBUG: Chewy strategies stack: [2] <- atomic @ **/chewy/lib/chewy/railtie.rb:17
Processing by ArticlesController#shared as HTML
  ArticlesIndex::Article Search (5.9ms) {:index=>["designs"], ***}
Rendered ActiveModel::Serializer::CollectionSerializer with ActiveModelSerializers::Adapter::JsonApi (2.3ms)
Completed 200 OK in 12ms (Views: 2.9ms | ActiveRecord: 0.0ms)
DEBUG: Chewy strategies stack: [2] -> atomic @ **/chewy/lib/chewy/railtie.rb:17

Since most developers are aware of their Chewy.request_strategy setting, there's no much need to remind them about it each time. So I decided to add a log message which will appear on server load (added to railties.rb). Also I've removed DEBUG: portion of a message because it's quite obvious anyway, and it is a responsibility of Logger::Formatter to format logs.
This is what it looks like now:

# somewhere in server load log
=> Run `rails server -h` for more startup options
Chewy strategies stack: [1] <- atomic

For every request that doesn't change strategy, it will not show any strategy messages:

Started GET "/articles" for 127.0.0.1 at 2017-07-22 20:25:44 +0300
Processing by ArticlesController#shared as HTML
  ArticlesIndex::Article Search (5.9ms) {:index=>["articles"], ***}
Rendered ActiveModel::Serializer::CollectionSerializer with ActiveModelSerializers::Adapter::JsonApi (2.3ms)
Completed 200 OK in 12ms (Views: 2.9ms | ActiveRecord: 0.0ms)

I have also added a now message when a strategy is removed from stack - that makes it much easier to follow strategy changes. And here's what happens if we wrap controller action with Chewy.strategy(:bypass) block:

Started GET "/articles" for 127.0.0.1 at 2017-07-22 20:25:44 +0300
Chewy strategies stack: [2] <- bypass @ **/app/controllers/articles_controller.rb:24
Processing by ArticlesController#shared as HTML
  ArticlesIndex::Article Search (5.9ms) {:index=>["articles"], ***}
Rendered ActiveModel::Serializer::CollectionSerializer with ActiveModelSerializers::Adapter::JsonApi (2.3ms)
Chewy strategies stack: [2] -> bypass, now atomic @ **/app/controllers/articles_controller.rb:24
Completed 200 OK in 12ms (Views: 2.9ms | ActiveRecord: 0.0ms)

That now atomic message shows which strategy will be used after bypass is removed from stack.

Please let me know if that makes sense.

[pyromaniac]

How about to make it less noisy without any setting?

[Borzik]

Usually I try to make PRs which don't change previous behavior (which becomes default one) because I don't know the reason why it was done that way. If you think there's no need for such setting and initial strategy log entry can be suppressed for everyone - I can do that. I myself would prefer that message to appear only on server startup, or never.

[pyromaniac]

Sure, agree, let's suppress it a bit

[Borzik]

@pyromaniac I've updated PR and its description. Please let me know your thoughts about it. Also let me know if the default request strategy notifier on server load is needed.

[pyromaniac]

Looks good, just fix Rubocop offences

[Borzik]

@pyromaniac done

[pyromaniac]

Cool, merged, thanks!