clean DSL module

[totothink]

No description provided.

[dblock]

👍

[totothink]

https://github.com/totothink/grape/blob/6a49d6c2086884770f9a322fa01d4fb3fd14c256/lib/grape/dsl/configuration.rb

      # Merge multiple layers of settings into one hash.
       def stacked_hash_to_hash(settings)
          return if settings.blank?
          settings.each_with_object({}) { |value, result| result.deep_merge!(value) }
        end

stacked_hash_to_hash method like procedural programming. It should serve as settings object method，you think?

[dblock]

@totothink Maybe ;)