move code to /lib

config.ru

@@ -1,3 +1,3 @@
-require_relative 'todo'
+require_relative 'lib/todo'
 
  run TodoAPI

lib/todo_repo.rb

@@ -0,0 +1,44 @@
+RecordNotFound = Class.new(StandardError)
+
+class TodoRepo
+  class << self
+    def todos
+      @todos ||= []
+      @todos
+    end
+
+    def add(params, host)
+      todo = Hashie.symbolize_keys!(params.to_hash)
+      id = SecureRandom.uuid
+      todo[:id] = id
+      todo[:url] = "#{host}/#{id}"
+
+      todos << todo
+      todo
+    end
+
+    def find(id)
+      todos.detect {|todo| todo[:id] == id}
+    end
+
+    def update(params)
+      params = Hashie.symbolize_keys(params.to_hash)
+      todo = find(params[:id])
+      raise RecordNotFound.new unless todo
+
+      todo.merge!(params)
+      todo
+    end
+
+    def delete(id)
+      todo = find(id)
+      raise RecordNotFound.new unless todo
+
+      todos.delete(todo)
+    end
+
+    def delete_all
+      @todos = []
+    end
+  end
+end

test/test_todo_api.rb

@@ -2,7 +2,7 @@
 
 require 'rack/test'
 require 'minitest/autorun'
-require_relative '../todo.rb'
+require_relative '../lib/todo.rb'
 
 class TodoAPITest < MiniTest::Test
   include Rack::Test::Methods