Should be able to set contextual validations

Contextual validations are active __only__ within
an appropriate context: either ”create" or ”update”.

validates(:name, :presence => true, :on => :create)

validates(:name, :presence => {:on => :update})

See http://edgeguides.rubyonrails.org/active_record_validations_callbacks.html#on

Should fix https://github.com/couchrest/couchrest_model/pull/90

lib/couchrest/model/base.rb

@@ -7,7 +7,6 @@ module CouchRest
       include CouchRest::Model::Configuration
       include CouchRest::Model::Connection
       include CouchRest::Model::Persistence
-      include CouchRest::Model::Callbacks
       include CouchRest::Model::DocumentQueries
       include CouchRest::Model::Views
       include CouchRest::Model::DesignDoc
@@ -21,6 +20,7 @@ module CouchRest
       include CouchRest::Model::Designs
       include CouchRest::Model::CastedBy
       include CouchRest::Model::Dirty
+      include CouchRest::Model::Callbacks
 
       def self.subclasses
         @subclasses ||= []