Added achievements event and listener in CubotPlugin

Plugin Cubot/src/main/java/net/simon987/cubotplugin/event/AchievementEvent.java

@@ -0,0 +1,23 @@
+package net.simon987.cubotplugin.event;
+
+import net.simon987.server.event.GameEvent;
+import net.simon987.server.game.objects.GameObject;
+
+public class AchievementEvent extends GameEvent {
+
+    private final String achievement;
+
+    public AchievementEvent(GameObject source, String achievement) {
+        this.achievement = achievement;
+        setSource(source);
+    }
+
+    public String getAchievement() {
+        return achievement;
+    }
+
+    @Override
+    public GameObject getSource() {
+        return (GameObject) super.getSource();
+    }
+}

Plugin Cubot/src/main/java/net/simon987/cubotplugin/event/AchievementListener.java

@@ -0,0 +1,27 @@
+package net.simon987.cubotplugin.event;
+
+import net.simon987.server.event.GameEvent;
+import net.simon987.server.event.GameEventListener;
+import net.simon987.server.game.objects.ControllableUnit;
+import net.simon987.server.game.objects.GameObject;
+import net.simon987.server.logging.LogManager;
+
+public class AchievementListener implements GameEventListener {
+    @Override
+    public Class getListenedEventType() {
+        return AchievementEvent.class;
+    }
+
+    @Override
+    public void handle(GameEvent event) {
+        AchievementEvent achievementEvent = (AchievementEvent) event;
+        GameObject object = achievementEvent.getSource();
+        if (object instanceof ControllableUnit) {
+            final String achievement = achievementEvent.getAchievement();
+            final ControllableUnit unit = (ControllableUnit) object;
+            LogManager.LOGGER.info(unit.getParent().getUsername() + " Completed achievement: " + achievement);
+
+            ((ControllableUnit) object).getParent().getStats().addToStringSet("achievements", achievement);
+        }
+    }
+}