title: Rails redirect_to with params
body: <p>I want to pass parameters (a hash) to <code>redirect_to</code>, how to do this? For example:</p>
  
  <pre><code>hash = { :parm1 =&gt; "hi", :parm2 =&gt; "hi" }
  </code></pre>
  
  <p>and I want to redirect to page <code>/hello</code></p>
  
  <p>URL like this: <code>/hello?parm1=hi&amp;parm2=hi</code></p>