Add horizon overrides enabled file.
diff --git a/horizon/files/enabled/horizon_overrides.py b/horizon/files/enabled/horizon_overrides.py
index e69de29..4595455 100644
--- a/horizon/files/enabled/horizon_overrides.py
+++ b/horizon/files/enabled/horizon_overrides.py
@@ -0,0 +1,4 @@
+
+ADD_INSTALLED_APPS = [
+    'horizon_overrides',
+]