title: Accessing the value of custom field in redmine plugin
body: <p>I am using Redmine 2.1 and I am writing a custom plugin. I am trying to access the value of a custom field on an issue.</p>
  
  <pre><code>  def controller_issues_edit_before_save(context = {})
      issue = context[:issue]
  
      add_assignee(issue)
    end
  </code></pre>
  
  <p>I am getting my issue then I pass it to a custom function.</p>
  
  <pre><code>private
    def add_assignee(issue)
      add_watcher_to_issue(issue, issue.custom_field_values {'bob'})
    end
  </code></pre>
  
  <p>I don't seem able to get the value of my custom field <code>bob</code>. <code>bob</code> is a user field.</p>
  
  <p>How do I get the value of my custom field?</p>