Adds back default constructor as removing it caused it to no longer load

src/main/java/net/knarcraft/stargate/Stargate.java

@@ -89,6 +89,13 @@ public class Stargate extends JavaPlugin {
     private FileConfiguration newConfig;
     private PluginManager pluginManager;
 
+    /**
+     * Empty constructor necessary for Spigot
+     */
+    public Stargate() {
+        super();
+    }
+
     /**
      * Special constructor used for MockBukkit
      *