[ADD] accounting: How is Odoo's multi-currency working?

https://docs.google.com/document/d/1QXNMvZn8pgwLKxDjEH4rIjbdPIn2rDtJHqEns6sgRLg/edit

accounting/others/multicurrencies/how_it_works.rst

@@ -1,3 +1,171 @@
 =====================================
 How is Odoo's multi-currency working?
-=====================================
+=====================================
+
+Overview
+========
+
+Choosing to use the multi-currency option in Odoo will allow you to send
+sales invoices, quotes and purchase orders or receive bills and payments
+in currencies other than your own. With multi-currency, you can also set
+up bank accounts in other currencies and run reports on your foreign
+currency activities.
+
+Configuration
+=============
+
+Turn on multi-currency
+----------------------
+
+In the accounting module, Go to :menuselection:`Configuration --> Settings` and flag
+**Allow multi currencies**, then click on **Apply**.
+
+.. image:: media/works01.png
+   :align: center
+
+Exchange Rate Journal
+---------------------
+
+The **Rate Difference Journal** records the differences between the payment
+registration and the expected amount. For example, if a payment is paid
+1 month after the invoice was issued, the exchange rate has probably
+changed. The fluctuation implies some loss or profit that are recorded
+by Odoo.
+
+You can change it in the settings:
+
+.. image:: media/works02.png
+   :align: center
+
+View or edit rate being used
+----------------------------
+
+You can manually configure the currency rates in :menuselection:`Configuration -->
+Currencies`. Open the currencies you want to use in Odoo and edit it.
+Make sure the currency is active.
+
+.. image:: media/works03.png
+   :align: center
+
+Click on **View Rates** to edit it and to see the history :
+
+.. image:: media/works04.png
+   :align: center
+
+Click on **Create** to add the rate. Fill in the date and the rate.
+Click on **Save** when you are done.
+
+.. image:: media/works05.png
+   :align: center
+
+Live Currency Rate
+------------------
+
+By default, the currencies need to be updated manually. But you can
+synchronize it with `Yahoo <https://finance.yahoo.com/currency-converter/>`__ or
+the `European Central Bank <http://www.ecb.europa.eu>`__. In 
+:menuselection:`Configuration --> Settings`, go to the **Live Currency Rate** section.
+
+Choose the interval : Manually, Daily, Weekly or Monthly. You can always
+force the update by clicking on **Update Now**. Select the provider, and you
+are set !
+
+.. image:: media/works06.png
+   :align: center
+
+.. note::
+
+	Only the **active** currencies are updated
+
+Configure your charts of account
+--------------------------------
+
+In the accounting application, go to :menuselection:`Adviser --> Charts of Accounts`.
+On each account, you can set a currency. It will force all moves for
+this account to have the account currency.
+
+If you leave it empty, it means that it can handle all currencies that
+are Active.
+
+.. image:: media/works07.png
+   :align: center
+
+Configure your journals
+-----------------------
+
+In order to register payments in other currencies, you have to remove
+the currency constraint on the journal. Go to the accounting
+application, Click on **More** on the journal and **Settings**.
+
+.. image:: media/works08.png
+   :align: center
+
+Check if the currency field is empty or in the foreign currency in which
+you will register the payments. If a currency is filled in, it means
+that you can register payments only in this currency.
+
+.. image:: media/works09.png
+   :align: center
+
+How is Odoo's multi-currency working?
+=====================================
+
+Now that you are working in a multi-currency environment, all
+accountable items will be linked to a currency, domestic or foreign.
+
+Sales Orders and Invoices
+-------------------------
+
+You are now able to set a different currency than the company one on
+your sale orders and on your invoices. The currency is set for the whole
+document.
+
+.. image:: media/works10.png
+   :align: center
+
+Purchases orders and Vendor Bills
+---------------------------------
+
+You are now able to set a different currency than the company one on
+your purchase orders and on your vendor bills. The currency is set for
+the whole document.
+
+.. image:: media/works11.png
+   :align: center
+
+Payment Registrations
+---------------------
+
+In the accounting application, go to **Sales > Payments**. Register the
+payment and set the currency.
+
+.. image:: media/works12.png
+   :align: center
+
+Bank Statements
+---------------
+
+When creating or importing bank statements, the amount is in the company
+currency. But there are now two complementary fields, the amount that
+was actually paid and the currency in which it was paid.
+
+.. image:: media/works13.png
+   :align: center
+
+When reconciling it, Odoo will directly match the payment with the right
+Invoice. You will get the invoice price in the invoice currency and the
+amount in your company currency.
+
+Exchange Rate Journal
+---------------------
+
+Go to :menuselection:`Adviser --> Journal Entries` and look for the Exchange difference
+journal entries. All the exchange rates differences are recorded in it.
+
+.. image:: media/works14.png
+   :align: center
+
+.. seealso::
+
+	* :doc:`invoices_payments`
+	* :doc:`exchange`