Create a Grails web application to maintains a list of authors and books.

Author:
  FirstName, LastName, Email address.
  None of the fields can be blank.
  Email address is unique.
  
Book:
  Title and ISBN number.
  Has at least one author
  May have more than one author
  ISBN has to be unique

Some sample data to create in the Bootstrap:

def burt = new Author(firstName: 'Burt', lastName: 'Beckwith', emailAddress: 'burt@example.com')
def jeff = new Author(firstName: 'Jeff', lastName: 'Brown', emailAddress: 'jeff@example.com')
def graeme = new Author(firstName: 'Graeme', lastName: 'Rocher', emailAddress: 'graeme@example.com')
def book1 = new Book(title: 'The Definitive Guide to Grails 2', isbn: '1430243775')
def book2 = new Book(title: 'Programming Grails', isbn: '1449323936')
burt.save()
jeff.save()
graeme.save()
book1.addToAuthors(jeff)
book1.addToAuthors(graeme)
book2.addToAuthors(burt)
book1.save()
book2.save()
