add a stubby Registry class

lib/Dancer2/Plugin/JsonApi/Registry.pm

@@ -0,0 +1,28 @@
+package Dancer2::Plugin::JsonApi::Registry;
+
+use 5.32.0;
+
+use Moo;
+
+use experimental qw/ signatures /;
+
+=head1 DESCRIPTION
+
+The registry for the different types of data managed by the plugin.
+
+=head1 METHODS
+
+=head2 serialize($type,$data,$meta={})
+
+Returns the serialized form of C<$data>.
+
+=cut
+
+sub serialize($self,$type,$data,$meta={}) {
+    return {};
+}
+
+1;
+
+__END__
+

t/compile.t

@@ -0,0 +1,8 @@
+use Dancer2::Plugin::JsonApi::Registry;
+
+use Test2::V0;
+
+# we have to start somewhere
+ok "it compiles!";
+
+done_testing;