lib/matchers/indexes/v3/have_index_for.rb in mongoid-rspec-4.1.0 vs lib/matchers/indexes/v3/have_index_for.rb in mongoid-rspec-4.2.0

@@ -42,10 +42,10 @@
       end
 
       private
 
       MAPPINGS = {
-        dropDups: :drop_dups
+        dropDups: :drop_dups # Deprecated from MongoDB 3.0
       }.freeze
 
       def denormalising_options(opts)
         options = {}
         opts.each_pair do |option, value|