title: Doctrine : Default value on joinColumn field
body: <p>New to symfony2 and Doctrine.</p>
  
  <p>How can I set a default value to the field <code>foo_id</code> (which is a reference on <code>Foo</code> table) to point on the <code>ID 1</code> of the Foo table (which exists in all cases) ?</p>
  
  <pre><code>Me\NavigationBundle\Entity\PublicText:
      type: entity
      table: public_text
      id:
          id:
              type: integer
              id: true
              generator:
                  strategy: AUTO
      fields:
          title:
              type: string
              length: '255'
              nullable: false
          content:
              type: string
              length: '2000'
              nullable: false            
      manyToOne:
          foo:
              #How to set a default value???
              targetEntity: \Me\NavigationBundle\Entity\Foo
              joinColumn:
                  name: foo_id
                  referencedColumnName: id   
                  nullable: false 
      lifecycleCallbacks: {  }
  </code></pre>
  
  <p>I tried a lot of things without success : </p>
  
  <ul>
  <li>Set default value to ID 1 in the constructor of Foo</li>
  <li>Perform a request to retrieve the Foo object of ID 1 in the Me entity (could works, but bad practice)</li>
  </ul>