More singleton marking.

git-svn-id: svn+ssh://src.earth.threerings.net/narya/trunk@5160 542714f4-19e9-0310-aa3c-eee0fc999fb1

src/java/com/threerings/crowd/server/PlaceRegistry.java

@@ -25,6 +25,7 @@ import java.util.Iterator;
 import java.util.List;
 
 import com.google.inject.Inject;
+import com.google.inject.Singleton;
 
 import com.samskivert.util.IntMap;
 import com.samskivert.util.IntMaps;
@@ -46,6 +47,7 @@ import static com.threerings.crowd.Log.log;
  * create new places and it will take care of instantiating and initializing a place manager to
  * manage newly created places.
  */
+@Singleton
 public class PlaceRegistry
     implements ShutdownManager.Shutdowner
 {