title: ransack_alias not doing anything in query
body: <p>I use Ransack for my search forms and I am attempting to use <code>ransack_alias</code> to shorten the queries. However, when I perform a search, the aliased fields don't filter the query at all. I have simplified my form to have only one simple alias and it doesn't seem to work.</p>
  
  <p>user model</p>
  
  <pre><code>class User &lt; ActiveRecord::Base
    ransack_alias :ec, :email_cont
  end
  </code></pre>
  
  <p>index.html.haml</p>
  
  <pre><code>= search_form_for @q, url: users_path, html: {method: :get} do |f|
    = f.label :ec
    = f.search_field :ec
    = f.submit 'Search'
  </code></pre>
  
  <p>If I put a breakpoint inside the controller:</p>
  
  <pre><code>&gt;&gt; User.count
  10
  
  &gt;&gt; User.ransack({email_cont: "test@email.com"}).result.count
  (93.8ms)  SELECT COUNT(*) FROM "users" WHERE ("users"."email" ILIKE '%test@email\.com%')
  1
  
  &gt;&gt; params[:q]
  {"ec" =&gt; "test@email.com"}
  
  &gt;&gt; User.ransack(params[:q]).result.count
  (28.4ms)  SELECT COUNT(*) FROM "users"
  10
  
  &gt;&gt; User._ransack_aliases
  {"ec" =&gt; "email_cont"}
  </code></pre>
  
  <p>What am I doing wrong here?</p>