title: Factory Girl Using Multiple Override properties
body: <p>I have a simple factory currently defined as: </p>
  
  <pre><code>factory :tm_event do
      ...
      category "MyString"
      category_id { Random.rand(1..2147483647) }
      ...
  end
  </code></pre>
  
  <p>I attempting to create a <code>TmEvent</code> object with the following: </p>
  
  <pre><code>FactoryGirl.create(:tm_event, category: 'rock', category_id: '12')
  </code></pre>
  
  <p>When this is run both category and category_id are set to <code>nil</code> within the resultant object. </p>
  
  <p>If I run with either category or category_id set individually then both instances are set with the corresponding property overridden. When I create an event directly <code>TmEvent.create(category: 'rock', category_id:'12')</code> then both attributes are populated. </p>
  
  <p>Is my syntax correct? 
  Where should I look for a solution?</p>