title: typeorm - how to add extra field to "many to many" table?
body: <p><strong>for example:</strong></p>
  
  <p>3 tables</p>
  
  <pre><code>user
  user_business_lines_business_line
  business_line
  </code></pre>
  
  <p>those created by <code>typeorm</code> with the declaration in <code>User</code></p>
  
  <pre><code>@ManyToMany(type =&gt; BusinessLine)
  @JoinTable()
  businessLines: BusinessLine[]
  </code></pre>
  
  <p>then, how to add columns fields like</p>
  
  <pre><code>@CreateDateColumn({ type: 'timestamp' })
  createdAt: Date
  
  @UpdateDateColumn({ type: 'timestamp' })
  updatedAt: Date
  </code></pre>
  
  <p>to <code>user_business_lines_business_line</code></p>