title: my own id in GORM
body: <p>I tried to change the standard 'id' in grails:</p>
  
  <pre><code>calls Book {
    String id
    String title
  
    static mapping {
      id generator:'assigned'
    }
  }
  </code></pre>
  
  <p>unfortunately, I soon noticed that this breaks my bootstrap. Instead of </p>
  
  <pre><code>new Book (id:'some ISBN', title:'great book').save(flush:true, failOnError:true)
  </code></pre>
  
  <p>I had to use</p>
  
  <pre><code>def b = new Book(title:'great book')
  b.id = 'some ISBN'
  b.save(flush:true, failOnError:true)
  </code></pre>
  
  <p>otherwise I get an 'ids for this class must be manually assigned before calling save()' error.</p>
  
  <p>but that's ok so far.</p>
  
  <p>I then encountered the same problem in the save action of my bookController. But this time, the workaround didn't do the trick.</p>
  
  <p>Any suggestions?</p>
  
  <p>I known, I can rename the id, but then I will have to change all scaffolded views...</p>