Fix deprecation notices (#44)

Using new Rails5 codepath to generate SQL

lib/polo/sql_translator.rb

@@ -70,7 +70,6 @@ def insert_values(record)
  # 'type_cast' call are necessary.
  #
  module ActiveRecordFour
-
  def insert_values(record)
  connection = ActiveRecord::Base.connection
  values = record.send(:arel_attributes_with_values_for_create, record.attribute_names)
@@ -88,13 +87,18 @@ def insert_values(record)
  # We now use the type_caster from the arel_table.
  #
  module ActiveRecordFive
- def insert_values(record)
-  type_caster = record.class.arel_table.send(:type_caster)
+ # Based on the codepath used in Rails 5
+ def raw_sql(record)
  values = record.send(:arel_attributes_with_values_for_create, record.attribute_names)
- values.each do |attribute, value|
- values[attribute] = type_caster.type_cast_for_database(attribute.name, value)
+ model = record.class
+ substitutes, binds = model.unscoped.substitute_values(values)
+
+ insert_manager = model.arel_table.create_insert
+ insert_manager.insert substitutes
+
+ model.connection.unprepared_statement do
+ model.connection.to_sql(insert_manager, binds)
  end
- values
  end
  end
 
@@ -103,7 +107,7 @@ def insert_values(record)
  elsif ActiveRecord::VERSION::MAJOR == 4
  include ActiveRecordFour
  else
- include ActiveRecordFive
+ prepend ActiveRecordFive
  end
  end
 end