Taking a vote. Which looks cleaner and more rubyesque?

instrument.rb

require 'ostruct'

class Instrument < OpenStruct

  def self.instruments_array
    InstrumentsCSVReader.get_from_file
  end

  def self.all
    @all ||= instruments_array.map { |n| new(n) }
  end

  def self.find(description)
    all.find { |n| n.name == description }
  end

  class InstrumentsCSVReader
    require 'csv'

    def self.get_from_file
      instruments_array=[]
      CSV.foreach("tmp/instruments.csv", headers: true) do |row|
        instruments_array << { colleague_code: row["Key"], name: row["Description"] }
      end
      instruments_array
    end
  end
end

instrument_array.rb

require 'ostruct'

class Instrument < OpenStruct

  def self.all
    @all ||= InstrumentsCSVReader.new.map { |n| new(n) }
  end

  def self.find(description)
    all.find { |n| n.name == description }
  end

  class InstrumentsCSVReader < Array
    require 'csv'

    def initialize
      super()
      get_from_file
    end

    def get_from_file
      CSV.foreach("tmp/instruments.csv", headers: true) do |row|
        self << { colleague_code: row["Key"], name: row["Description"] }
      end
    end
  end
end