Where is my _rev field from couchdb


I am using logstash to put my data from couchdb into elasticsearch. I just noticed that my _rev field in not ported to elasticsearch. Do I need to do something special in my logstash config file to have that in elasticsearch. Prompt help will be appreciated. I only have input and output sections in my logstash config file.
Here is my input in logstash config file:

couchdb_changes {
    db => "users"
    sequence_path => "seq_files\users_couchdb_seq"
    tags => ["users"]

and here is my output:

if "users" in [tags] {
   elasticsearch { 
   document_id => "%{[@metadata][_id]}"
   index => "users_index"
   hosts => [""]


This appears to be a duplicate of: Where is my _rev field