title: How to find all records where date is later than?
body: <p>I have a firebase db like the one below:</p>
  
  <p><a href="https://i.stack.imgur.com/srYzg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/srYzg.png" alt="enter image description here"></a></p>
  
  <p>and I'd like to select all events that come after a certain date.  I've attempted to do this with the following code:</p>
  
  <pre><code>events := []data.EventData{}
  
  if err := ref.Child("date").OrderByValue().StartAt(time.Now()).Get(c, events); err != nil {
      fmt.Println("Error selecing upcoming events")
      fmt.Println("Error:", err)
      response.Message = "Problem getting upcoming events"
      c.JSON(http.StatusInternalServerError, response)
      return
  }
  </code></pre>
  
  <p>But it keeps throwing the error:</p>
  
  <blockquote>
    <p>Index not defined, add ".indexOn": ".value", for path "/Event/date",
    to the rules</p>
  </blockquote>
  
  <p>What does this mean and how do I go about selecting the records that I need?  Am I on the right track and just need to resolve this error or should I be taking a different approach?</p>