title: how to load modules in different folders
body: <p>I have following folder structure</p>
  
  <p>--<strong>folder1</strong><br>
  ------main.lua<br>
  ------<strong>sub_folder</strong><br>
  ---------func1.lua<br>
  --<strong>folder2</strong><br>
  ------func2.lua  </p>
  
  <p>I want to load <code>func1.lua</code> and <code>func2.lua</code> in <code>main.lua</code> by <code>require</code> command</p>
  
  <p>PS:what does the init.lua in a folder do</p>