diff --git a/overrides.json b/overrides.json
new file mode 100644
index 0000000..ee224a7
--- /dev/null
+++ b/overrides.json
@@ -0,0 +1,7 @@
+{
+    "@jupyterlab/docmanager-extension:plugin": {
+         "defaultViewers": {
+        "markdown": "Jupytext Notebook"
+      }
+    }
+  }
\ No newline at end of file
diff --git a/postBuild b/postBuild
new file mode 100644
index 0000000..ee580cb
--- /dev/null
+++ b/postBuild
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+set -eux
+
+mkdir -p ${NB_PYTHON_PREFIX}/share/jupyter/lab/settings
+cp overrides.json ${NB_PYTHON_PREFIX}/share/jupyter/lab/settings
\ No newline at end of file