How to get model attributes to save in order? - ruby-on-rails

Question

I'm building a quiz app, to create a quiz I do this:
def new
#quiz = Quiz.new
50.times do
question = #quiz.questions.build
5.times { question.answers.build }
end
end
enter code here
Which uses nested parameters. The problem is, sometimes the quiz doesn't save in order (such as when I create a new quiz OR I update an existing quiz). If I create a quiz in particular order, say Question 1, Question 2, Question 3, I want the questions in that quiz to remain in the same order after I update or create it. Right now, if I update a quiz the order gets jumbled up if I want to show the quiz using something like quiz.questions.each do |question|
I wasn't aware that ruby databases don't enforce order, so how do I make sure that if I create a quiz, the order in which I enter the questions (top to bottom) will always be the order that the questions are presented in?
If you are interested, this is the form I use to create the quiz:
<%= form_for(#quiz) do |f| %>
<% if #quiz.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#quiz.errors.count, "error") %> prohibited this quiz from being saved:</h2>
<ul>
<% #quiz.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %><br>
<%= f.text_field :name %>
</div>
<div class = 'field'>
<%= f.label :difficulty, "Difficulty of Quiz, 1 to 3 with 3 being most difficult" %>
<%= f.text_field :difficulty %>
</div>
<div class="field">
<%= f.label :for_unsubscribed, "Check to have this quiz be visible to logged in but unsubscribed users" %>
<%= f.check_box :for_unsubscribed %>
</div>
<%= f.fields_for :questions do |question_attribute| %>
<div class = 'inner-c'>
<p>
<%= question_attribute.label :content, "Question" %> <span><b><%= question_attribute.index + 1 %></b></span> <br/>
<%= question_attribute.text_area :content, :cols => 100, :rows => 4 %>
</p>
<p>
<%= question_attribute.label :explanation, "Answer Explanation" %> <br/>
<%= question_attribute.text_area :explanation, :cols => 100, :rows => 6 %>
</p>
<%= question_attribute.label :_destroy, "Remove Question"%>
<%= question_attribute.check_box :_destroy %><br/>
<%= question_attribute.label :passage, "Reference Passage" %> <br/>
<%= question_attribute.text_area :passage, :rows => 3, :class => 'passage-input' %>
<%#= question_attribute.label :question_explanation, "Question Explanation" %>
<%#= question_attribute.text_area :question_explanation, :rows => 10 %>
</p>
<%= question_attribute.fields_for :answers do |answer_attribute| %>
<p>
<%= answer_attribute.label :content, "Answer" %>
<%= answer_attribute.text_field :content %>
<%= answer_attribute.label :correct_answer, "Check to indicate correct answer", :class => 'inline' %>
<%= answer_attribute.check_box :correct_answer, :class => 'inline'%>
</p>
<% end %>
</div> <!-- inner-c -->
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>