title: GORM tablePerHierarchy doesn't create tables
body: <p>I need to have two domains which are extends from one domain. However when i create the domains subdomains' tables are not created.</p>
  
  <pre><code>class BaseEntity {
    Date created
    Boolean isDeleted
    Date modified
    Integer version
  
    static mapping = {
      tablePerHierarchy false
      version false
      table name: "base_entity",  schema: "user"
      isDeleted defaultValue: Boolean.FALSE
    }
  }
  </code></pre>
  
  <p>First domain extends from BaseEntity</p>
  
  <pre><code>class UserEx extends BaseEntity {
    String firstName
    String lastName
    String password
    String userName
  
    static mapping = {
      version false
      table name: "user_ex",  schema: "user"
    }
  }
  </code></pre>
  
  <p>This is the second domain</p>
  
  <pre><code>class UserType extends BaseEntity {
    Integer name
  
    static belongsTo = [parent: UserType]
    static hasMany = [child:UserType]
  
    static mapping = {
      version false
      table name: "user_type",  schema: "user"
    }
  }
  </code></pre>
  
  <p>In the db the only created table is BaseEntity. If i remove tablePerHierarchy property from BaseEntity domain, created table(which is BaseEntity) contains all fields of userEx and userType - this is not we like to have-</p>
  
  <p>To sum up I want to have those three tables in my db without losing extends relationship.</p>
  
  <p>Thanks in advance</p>