title: Creating multiple objects on one-to-one relationship
body: <p>Helo, I had stuck with this problem.
  Just to make things simple i'll explain it shorter.</p>
  
  <pre><code>Student has_many   :grades
          belongs_to :class
  
  Grade belongs_to   :student
        belongs_to   :rubric
  
  Rubric belongs_to  :course
         has_many    :students, :through =&gt; :class
  </code></pre>
  
  <p>To create new grade we need to find existent students. We can call @class.students to do so. Also, grade should be created with rubric_id. </p>
  
  <p>I've already found out how to do nested forms. But how to pass plural student id's to new grades?</p>
  
  <p>How to build controller and view to do so? </p>