 <p>The error tells you exactly where the problem is. </p> <pre><code>add has_many :bookmarks to app/models/user.rb add belongs_to :user to app/model/user.rb </code></pre> <p>this should not be in a migration since they do not change the schema. You need to add these to the bookmark and user model, so</p> <pre><code>class Bookmark &lt; ActiveRecord::Base belongs_to :user end class User &lt; ActiveRecord::Base has_many :bookmarks end </code></pre>