title: CreateIndex with Binding Objects
body: <p>I have a collection that includes a field of type Time. I need to be able to query this collection by year, or month-year combination.</p>
  
  <p>I have tried using the index creation tool on the web site itself, using things like <code>Year(data.expDate)</code> and <code>Month(data.expDate)</code> in the Terms, but this did not work.</p>
  
  <p>Here is the schema for my collection:</p>
  
  <pre><code>type Expense {
    _id: ID!
    expAmount: Float!
    expDate: Time!
    expCategory: Category!
    _ts: Long!
  }
  </code></pre>
  
  <p>I need to be able to list the expenses for a particular year, or a particular month-year, without having to create separate month and year fields in my collection.</p>