module Constants
  CONST1="value"
  CONST2="value2"
end

module Constants
  module Group1
    CONST1="value"
    CONST2="value2"
  end
  module Group2
   # some relevant constants
  end
end

module Constants
  module Foo
    extend self

    BAR = 'bar'
    def bar
      BAR
    end
  end
end