Today I worked on adding a company name to my signup form. In order for me to get the form to work correctly I discovered that I needed the rails method accepts_nested_attributes_for in my company model:

class Company < ActiveRecord::Base
  has_many :users, dependent: :destroy
  validates :name, presence: true, length: { maximum: 75 }
  validates :plan, presence: true
  accepts_nested_attributes_for :users

And then inside your ‘new action’ inside of your companies controller you need to make sure a new user gets created as part of a company:

def new
  @company =
  @user =

Now finally we can work on our form. The first part of the form you do regularly and pass in @company into the form_for method. And then you notice that we have a fields_for section for the part of the form that has to deal with users.

<%= form_for(@company) do |f| %>
  <%= render 'shared/error_messages', object: f.object %>
  <%= f.label :company %>
  <%= f.text_field :name %>

  <%= f.fields_for :users do |user| %>

    <%= user.label :name %>
    <%= user.text_field :name %>

    <%= user.label :email %>
    <%= user.text_field :email %>

    <%= user.label :password %>
    <%= user.password_field :password %>

    <%= user.label :password_confirmation, "Confirmation" %>
    <%= user.password_field :password_confirmation %>

  <% end %>

  <%= f.submit "Create my account", class: "btn btn-large btn-primary" %>

And that’s pretty much all you have to do in order to get a nested form to work.