riversong code showcase

Source/Engine/Core/Groups/DefaultGameSystemGroup.cs

@@ -0,0 +1,6 @@
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    public class DefaultGameSystemGroup : GameSystemGroup
+    {
+    }
+}

Source/Engine/Core/Groups/EarlyGameSystemGroup.cs

@@ -0,0 +1,9 @@
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [InitializeBefore(typeof(DefaultGameSystemGroup))]
+    [UpdateBefore(typeof(DefaultGameSystemGroup))]
+    [DisposeBefore(typeof(DefaultGameSystemGroup))]
+    public class EarlyGameSystemGroup : GameSystemGroup
+    {
+    }
+}

Source/Engine/Core/Groups/LateGameSystemGroup.cs

@@ -0,0 +1,9 @@
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [InitializeAfter(typeof(DefaultGameSystemGroup))]
+    [UpdateAfter(typeof(DefaultGameSystemGroup))]
+    [DisposeAfter(typeof(DefaultGameSystemGroup))]
+    public class LateGameSystemGroup : GameSystemGroup
+    {
+    }
+}

Source/Engine/Core/Groups/RootGameSystemGroup.cs

@@ -0,0 +1,7 @@
+namespace DanieleMarotta.RiversongCodeShowcase
+{
+    [DisableDiscovery]
+    public class RootGameSystemGroup : GameSystemGroup
+    {
+    }
+}