title: Grails many to one and belongsTo
body: <p>Let's say I have two domain objects as seen below,</p>
  
  <pre><code>class Author {
      static hasMany = [books: Book]
      String name
  }
  
  class Book {
      String title
      static belongsTo=[author:Author]
  }
  </code></pre>
  
  <p>If I wanted to create a <code>Book</code>, I will have to create an <code>Author</code> first and if I wanted to create an <code>Author</code> I will need to create some <code>books</code>. So would I have to create a <code>Book</code> and <code>Author</code> at the same time?</p>