Fix smart_restart task to check if puma preloads app

[sponomarev]

I was faced with a conflict between phased restart and puma's preload_app.

set :puma_threads, [4, 4]
set :puma_workers, 2
set :puma_preload_app, true

With this config gem invokes phased-restart, which is not recommended for preload_app.

My changes makes gem not to rely only on puma_workers, but also on puma_preload_app, to decide what restart method to be invoked.

[seuros]

can you please link to where is stated that not recommended for preloaded app to be phase restarted ?

[sponomarev]

@seuros Easily! In puma gems docs.

Note that preload_app can’t be used with phased restart, since phased restart kills and restarts workers one-by-one, and preload_app is all about copying the code of master into the workers.

https://github.com/puma/puma/blob/master/README.md#clustered-mode the last paragraph

[seuros]

Thanks you