Fixed invenio plugin

invenio/plugin/custom_invenio_plugin/views.py

@@ -0,0 +1,17 @@
+from flask import Blueprint
+from flask_menu import current_menu
+
+blueprint = Blueprint(
+    "custom_menu",
+    __name__,
+)
+
+
+@blueprint.before_app_first_request
+def init_menu():
+    """Add custom items to main menu."""
+    current_menu.submenu("main").register(
+        "About AM-D-Model",
+        "https://am-d-model.eu",
+        order=0,
+    )