Add a Readyset.configure method that allows users to configure our gem

[ethan-readyset]

Brief Description of Feature:
We should add a Readyset.configure method that allows users to configure our gem similar to what is done here.

Background:
The typical way to configure a gem in the context of a Rails application seems to be to add a file for the gem in the config/initializers directory and then invoke GemName.configure. Readyset.configure should take a block and yield a Readyset::Configuration object to that block like so:

Readyset.configure do |config|
  config.option1 = ...
  config.option2 = ...
end

---

Optional information to add

Proposed Solution:
Internally, we should define Readyset.configuration and Readyset.configure methods like so:

lib/readyset.rb
module Readyset
  def self.configuration
    @configuration ||= Configuration.new
  end

  class << self
    delegate :configure, to: :configuration
  end
end

# lib/readyset/configuration.rb
module Readyset
  class Configuration
    def configure
      yield(self)
    end
  end
end

Readyset::Configuration should specify attr_accessors for any of the configuration options we'd like to support. We could also consider making Readyset::Configuration a module since it will only ever have one instance. I don't think we should mixin that module because I don't want Readyset to be overloaded with too much state, but we could do something like this:

lib/readyset.rb
module Readyset
  class << self
    delegate :configure, to: :Configuration
  end
end

# lib/readyset/configuration.rb
module Readyset
  module Configuration
    attr_accessor :option_1, ...

    @option_1 = 'option 1 default value'
    ...

    def self.configure
      yield(self)
    end
  end
end

[helpotters]

Starting on this issue now. I'll use the gem you linked as a reference. Thank you for finding that! It's perfect.