[ADD] Inventory: How to choose between minimum stock rule and make to order

https://docs.google.com/document/d/1Euf2MFlhXsLzNRal8tYF8cZL0a0KQTx19xpmYKCNnmg/edit#heading=h.tum9sox5i0c

inventory/management/adjustment.rst

@@ -7,3 +7,4 @@ Inventory Adjustment
    :glob:
 
    adjustment/initial_inventory
+   adjustment/min_stock_rule_vs_mto

inventory/management/adjustment/min_stock_rule_vs_mto.rst

@@ -0,0 +1,74 @@
+==========================================================
+How to choose between minimum stock rule and make to order
+==========================================================
+
+**Minimum Stock rules** and **Make to Order** have similar consequences but
+different rules. They should be used depending on your manufacturing and
+delivery strategies.
+
+Terminology
+===========
+
+Minimum stock rule 
+-------------------
+
+**Minimum Stock** rules are used to ensure that you always have the minimum
+amount of a product in stock in order to manufacture your products
+and/or answer to your customer needs. When the stock level of a product
+reaches its minimum the system will automatically generate a procurement
+with the quantity needed to reach the maximum stock level.
+
+Make to Order
+-------------
+
+The **Make to Order** function will trigger a **Purchase Order** of the amount
+of the **Sales Order** related to the product. The system will **not** check
+the current stock valuation. This means that a draft purchase order will
+be generated regardless of the quantity on hand of the product.
+
+Configuration
+=============
+
+Minimum stock rules
+-------------------
+
+The Minimum Stock Rules configuration is available through the menu 
+:menuselection:`Inventory --> Inventory Control --> Reordering Rule`
+in the drop down menu. There, click on **Create** to set minimum and
+maximum stock values for a given product.
+
+.. image:: media/min_stock_rule_vs_mto01.png
+   :align: center
+
+.. demo:fields:: stock.action_orderpoint_form
+
+Then, click on your product to access the related product form and, on
+the **Inventory submenu**, do not forget to select a supplier.
+
+.. image:: media/min_stock_rule_vs_mto02.png
+   :align: center
+
+.. tip::
+    Don’t forget to select the right product type in the product form. 
+    A consumable can not be stocked and will thus not be accounted for in the stock valuation.
+
+Make to Order 
+--------------
+
+The Make to Order configuration is available on your product form
+through your :menuselection:`Inventory module --> Inventory control --> Products`
+(or any other module where products are available).
+
+On the product form, under **Inventory**, click on **Make To Order**.
+
+.. image:: media/min_stock_rule_vs_mto03.png
+   :align: center
+
+Choice between the two options
+------------------------------
+
+The choice between the two options is thus dependent of your inventory
+strategy. If you prefer to have a buffer and always have at least a
+minimum amount, the minimum stock rule should be used. If you want to
+reorder your stocks only if your sale is confirmed it is better to use
+the Make to Order.