refactor site_updated, add initial site file tracking

ext/sequel/plugins/create_timestamp.rb

@@ -0,0 +1,8 @@
+module Sequel::Plugins::CreateTimestamp
+  module InstanceMethods
+    def before_create
+      self.created_at = Time.now if respond_to?(:created_at) && !self.created_at
+      super
+    end
+  end
+end

ext/sequel/plugins/paranoid_delete.rb

@@ -0,0 +1,32 @@
+module Sequel
+  module ParanoidDelete
+
+    def self.included(base)
+      base.extend(ClassMethods)
+    end
+
+    # Instead of actually deleting, we just set is_deleted to true,
+    # and look for it with our default dataset filter.
+    def delete
+      self.is_deleted = true
+      save :validate => false
+      true
+    end
+
+    module ClassMethods
+
+      # There's no hook for setting default filters after inheritance (that I'm aware of),
+      # so this adds the filter for the first time the class' dataset is accessed for the new model.
+      def dataset
+        if @_is_deleted_filter_set.nil?
+          @dataset.filter! is_deleted: false
+          @_is_deleted_filter_set = true
+        end
+        super
+      end
+
+    end
+  end
+
+  # Model.include ParanoidDelete
+end