Add after init callback (#89)

* Add after init callback

* Test the after_initialize callback

lib/literal/properties/schema.rb

@@ -94,6 +94,7 @@ def generate_initializer_body
 		[
 			"@literal_properties = self.class.literal_properties",
 			generate_initializer_handle_properties(@sorted_properties),
+			"after_initialize if respond_to?(:after_initialize)",
 		].join("\n")
 	end
 

test/properties.test.rb

@@ -80,3 +80,21 @@ class WithNilableType
 	prop_name = props.first
 	assert(prop_name.optional?) { "Expected name to be optional" }
 end
+
+test "after initialize callback" do
+	callback_called = false
+
+	example = Class.new do
+		extend Literal::Properties
+
+		prop :name, String
+
+		define_method :after_initialize do
+			callback_called = true
+		end
+	end
+
+	example.new(name: "John")
+
+	assert callback_called
+end