Add form / view to edit purchase order details

- Cannot edit the COMPANY if there are line items already

InvenTree/order/forms.py

@@ -7,10 +7,35 @@ from __future__ import unicode_literals
 
 from InvenTree.forms import HelperForm
 
-from .models import PurchaseOrderLineItem
+from .models import PurchaseOrder, PurchaseOrderLineItem
+
+
+class IssuePurchaseOrderForm(HelperForm):
+
+    class Meta:
+        model = PurchaseOrder
+        fields = [
+            'status',
+        ]
+
+
+class EditPurchaseOrderForm(HelperForm):
+    """ Form for editing a PurchaseOrder object """
+
+    class Meta:
+        model = PurchaseOrder
+        fields = [
+            'reference',
+            'supplier',
+            'description',
+            'URL',
+            'status',
+            'notes'
+        ]
 
 
 class EditPurchaseOrderLineItemForm(HelperForm):
+    """ Form for editing a PurchaseOrderLineItem object """
 
     class Meta:
         model = PurchaseOrderLineItem