def drop(key = nil)
      if key
        index = self[key] or return false
        name = index["name"]
      else
        name = "*"
      end
      result = database.command deleteIndexes: collection_name, index: name
      result["ok"] == 1
    end
def drop(key = nil)
      if key
        index = self[key] or return false
        name = index["name"]
      else
        name = "*"
      end
      result = database.command deleteIndexes: collection_name, index: name
      result["ok"] == 1
    end
Drop an index, or all indexes.

 @example Drop all indexes
   session[:users].indexes.count # => 3
   # Does not drop the _id index
   session[:users].indexes.drop
   session[:users].indexes.count # => 1

 @example Drop a particular index
   session[:users].indexes.drop(name: 1)
   session[:users].indexes[name: 1] # => nil

 @param [ Hash ] key The index's key.

 @return [ Boolean ] Whether the indexes were dropped.

 @since 1.0.0