title: belongs_to not making join
body: <p>I have users table with:</p>
  
  <ul>
  <li>id</li>
  <li>username</li>
  </ul>
  
  <p>and questions table with </p>
  
  <ul>
  <li>id</li>
  <li>asker_id</li>
  <li>question_text</li>
  </ul>
  
  <p>So when I need to get a question from db I need the username too.</p>
  
  <p>So I made:</p>
  
  <pre><code>class User &lt; ActiveRecord::Base
      has_many :questions
  end
  
  class Question &lt; ActiveRecord::Base
      validates :question_text, presence: true
      belongs_to :user, foreign_key: "asker_id"
  end
  
  #controller
  def index
      @questions = Question.order(id: 'desc')
  end
  
  #view
  &lt;strong&gt;&lt;%= question.user.username %&gt;:&lt;/strong&gt;
  &lt;%= question.question_text %&gt; at 
  &lt;i&gt;&lt;%= question.created_at %&gt;&lt;/i&gt;
  </code></pre>
  
  <p>I was expecting that questions to make join to users but in console I see:</p>
  
  <pre><code>  Question Load (0.2ms)  SELECT "questions".* FROM "questions"  ORDER BY "questions"."id" DESC
    User Load (0.1ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1  [["id", 1]]
    CACHE (0.1ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1  [["id", 1]]
    CACHE (0.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1  [["id", 1]]
    CACHE (0.0ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = ? LIMIT 1  [["id", 1]]
  </code></pre>
  
  <p>How do I get a join?</p>