title: get for many to many relations
body: <pre><code>Tag:
    columns:
      name:              
        type: string(100)
  
  TagNews:
    columns:
      tag_id:  
        type: integer
        primary: true
      news_id:   
        type: integer
        primary: true 
    relations:
      Tag:     { onDelete: CASCADE, local: tag_id, foreign: id }
      News:      { onDelete: CASCADE, local: news_id, foreign: id }
  
  News:
    columns:
      tag_id:        
        type: integer
      name:               
        type: string(100)
    relations:
      Tag:
        class: Tag
        refClass: TagNews
        local: news_id
        foreign: tag_id
        foreignAlias: TagNews
  
  
  TAG:
  | id | name |
  | 1  | tag1 |
  | 2  | tag2 |
  | 3  | tag3 |
  
  
  TagNews:
  | id_tag | tag_news |
  | 1      |  1       |
  | 2      |  1       |
  | 2      |  2       |
  | 3      |  2       |
  | 3      |  3       |
  | 1      |  3       |
  
  News:
  
  | id  | name  |
  | 1   | news1 |
  | 2   | news2 |
  | 3   | news3 |
  | 4   | news4 |
  | 5   | news5 |
  </code></pre>
  
  <p>how can i get all news for tag1 etc?</p>
  
  <p>for example <strong>site.com/tag/tag1</strong> ?
  what i must write in action.class and template? i use Symfony 1.4 and Doctrine 1.2</p>