title: How I realize master page in Rails just as in .NET
body: <p>so,I am a beginner,I know there is <code>layout</code> in rails .</p>
  
  <p>but I want a shared part that many pages will use,include all of the <code>mvc</code> other than just <code>v</code>
  .just like the master page in .Net webform.</p>
  
  <p>for example .every site will own may manage pages,and this pages will use a common left sidebar which is consists of a few menus.</p>
  
  <p>how can I realize this? </p>