Rails: Reference to new Model throwing error - ruby-on-rails

Question

I have a working users table.
I have generated a new table using:
rails generate model quiz_answers
..and run rake db:migrate
My CreateQuizAnswers migration file looks like this:
class CreateQuizAnswers < ActiveRecord::Migration
def change
create_table :quiz_answers do |t|
t.references :user, index: true
t.string :answer1
t.string :answer2
t.string :answer3
t.string :answer4
t.string :answer5
t.string :answer6
t.string :answer7
t.string :answer8
t.timestamps
end
end
end
I have a quiz_answer model:
class QuizAnswer < ActiveRecord::Base
belongs_to :user
end
and a QuizAnswersController:
class QuizAnswersController < ApplicationController
def new
#user = current_user
#quiz_answer = current_user.quiz_answer.build
end
private
def post_params
params.require(:quiz_answer).permit(:body, :user_id)
end
end
I have added :quiz_answers as a resource in routes.rb
Edited question:
WHY, then, when I try to build a form (using Devise) do I get the error "undefined method `body' for...(with a reference to QuizAnswer here)"? I have another model 'Post' which does not generate this error and does not have a 'body' attribute.
The page where I'm trying to build the form is home/whattypeofleader.html.erb and, in routes.rb I have:
get "whattypeofleader" => "home#whattypeofleader"
And in my HomeController I have:
class HomeController < ApplicationController
def index
end
def whattypeofleader
#user = current_user
#quiz_answer = current_user.quiz_answer.build
end
end
What the HELL am I doing wrong? Any help desperately appreciated, thanks.
Oh, and in case you need it, here's the form code, a partial that gets 'rendered' in whattypeofleader:
<%= form_for([current_user, #quiz_answer]) do |f| %>
<p>
<%= f.text_area :body, :autofocus => true , :class => "elearning-input"%>
</p>
<p>
<%= f.submit("Save entry") %>
</p>
<% end %>

Answer 1

<%= form_for([current_user, #quiz_answer]) do |f| %>
#...
<%= f.text_area :body, :autofocus => true , :class => "elearning-input"%>
You are creating a text_area here, and you tell rails to bind this text area input with a #quiz_answer.body attribute. Why?
form_for assigns last element of an array to be a form's object. It yield a form builder object (f), which keeps a reference to this object (f.object). All the fields created with this form builder are automatically populated with a value of f.object.send(:field_name) (it also set up a name of the fields, so the params can be easily matched when it is posted). This is rails magic making all the form fields populated with model's data.
Since your model does not have body attribute (no such column in your database and no method with that name defined), f.object.send(:body) throws a method undefined error.
Regarding the fix to that, you need to decide how this form is to look for. Your models contain 8 columns, answer<i> (which is worrying and suggests you might wanna use association here).