visitors.rb in arel-2.0.5

- old
+ new

@@ -1,5 +1,6 @@
 require 'arel/visitors/visitor'
+require 'arel/visitors/depth_first'
 require 'arel/visitors/to_sql'
 require 'arel/visitors/sqlite'
 require 'arel/visitors/postgresql'
 require 'arel/visitors/mysql'
 require 'arel/visitors/oracle'