Add a hopefully functional implementation

Time to test

handlers/main.yml

@@ -0,0 +1,9 @@
+#!/usr/bin/ansible-playbook
+# vim:ft=ansible:
+---
+- name: "restart terraria {{ terraria_name }}"
+  systemd:
+    name: "terraria@{{ terraria_name }}"
+    state: restarted
+  become: yes
+  when: terraria_enabled