Add MaterializeCSS styles (#1)

## Changes
* Adds the [AssetPack](https://metacpan.org/pod/Mojolicious::Plugin::AssetPack) Mojolicious plugin
* Adds the [MaterializeCSS](https://www.npmjs.com/package/materialize-css) Node package
* Applies styles to app

Reviewed-on: #1

mojo_app/lib/MojoApp.pm

@@ -10,6 +10,9 @@ sub startup ($self) {
   # Configure the application
   $self->secrets($config->{secrets});
 
+  $self->plugin(AssetPack => {pipes => [qw(Css)]});
+  $self->asset->process("app.css" => ("materialize.css"));
+
   # Router
   my $r = $self->routes;