title: How to create a child model from a parent
body: <p>I've been spinning may wheels with Rails on this for a few days.  I'm working with three models: <code>IngredientBase</code>, <code>Ingredient</code>, and <code>IngredientList</code>. <code>IngredientBase</code> contains a string that may be "Chicken", "Eggs", or "Bacon." Ingredient will have a single <code>Ingredient</code> and a quantity. <code>IngredientList</code> will have many Ingredients.  </p>
  
  <p>I want the user to be able to ingredient_lists/new and be able to create several Ingredients before submitting the <code>IngredientList</code>. How could I do this without having the user submit multiple forms?</p>