🧑‍💻 accepts_nested_attributes_for and attr_accessible

In your model, if you have {% highlight ruby %} accepts_nested_attributes_for :attachments {% endhighlight %} And you limit the accessible attributes with something like {% highlight ruby %} attr_accessible :title, :text {% endhighlight %} make sure to also include the virtual attribute for the nested model to that list, like so: {% highlight ruby %} attr_accessible :title, :text, :attachments_attributes {% endhighlight %} Otherwise, your model won't accept the nested attributes.