[ADD] b_purchase_manual_date_planned : init for null values

beesdoo_purchase_manual_date_planned/models/purchase.py

@@ -9,6 +9,23 @@ class PurchaseOrder(models.Model):
         string="Scheduled Date", required=True
     )
 
+    def init(self,cr):
+        cr.execute(
+            """
+            UPDATE purchase_order
+            SET manual_date_planned = (SELECT date_planned
+                FROM purchase_order_line
+                    WHERE purchase_order_line.order_id = purchase_order.id
+                    AND purchase_order_line.date_planned IS NOT NULL
+                    LIMIT 1)
+            """
+        )
+        cr.execute(
+            """
+            ALTER TABLE purchase_order ALTER COLUMN manual_date_planned SET NOT NULL
+            """
+        )
+
     @api.onchange("order_line", "order_line.date_planned")
     def _on_change_manual_date_planned(self):
         """