title: How to query data from different collections and sort by date?
body: <p>I stumbled upon problem that my search results are of a mixed data, which is located in different collections (posts/venues/etc), currently Im doing separate requests to retrieve this data, but its obviously sorted among its types (posts array, venues array)
  How can I query multiple collections (posts/venues) and sort them by date/any other parameter (via mongoose)?
  or maybe there is a better solution?
  Thanks</p>