[ADD] accounting: How to manage a bank in a foreign currency?

https://docs.google.com/document/d/1JlucOaOUGa7NTg3flyt-d5E6sHMNPSEgMPR8dPJ6XVA/edit#

accounting/bank/reconciliation.rst

@@ -5,5 +5,4 @@ Bank Reconciliation
 .. toctree::
    :titlesonly:
 
-   setup/create_bank_account
-   setup/manage_cash_register
+   reconciliation/use_cases

accounting/bank/setup.rst

@@ -5,4 +5,6 @@ Setup
 .. toctree::
    :titlesonly:
 
-   reconciliation/use_cases
+   setup/create_bank_account
+   setup/manage_cash_register
+   setup/foreign_currency

accounting/bank/setup/foreign_currency.rst

@@ -0,0 +1,117 @@
+===========================================
+How to manage a bank in a foreign currency?
+===========================================
+
+In Odoo, every transaction is recorded in the default currency of the
+company. Reports are all based on the currency of the company. But for
+transactions occurring in another currency, Odoo stores both the value
+in the currency of the company and the value in the currency of the
+transaction.
+
+When you have a bank account in a foreign currencies, for every
+transaction, Odoo stores two values:
+
+-  The debit/credit in the currency of the company
+
+-  The debit/credit in the currency of the bank account
+
+Currency rates are updated automatically using yahoo.com, or the
+European Central bank web-services.
+
+Configuration
+=============
+
+Activate the multi-currency feature
+-----------------------------------
+
+In order to allow your company to work with multiple currencies, you
+should activate the multi-currency mode. In the accounting application,
+go into :menuselection:`Configuration --> Settings --> Accounting & Finance Features`
+make sure the **Allow Multi-currencies** box is ticked. Provide
+a **Currency Exchange Gain / Loss** account, then click on **Apply**.
+
+Configure currencies
+--------------------
+
+Once the Odoo is configured to support multiple currencies, you should
+activate the currencies you plan to work with. To do that, go the menu
+:menuselection:`Configuration --> Currencies`. All the currencies are created by default,
+but you should activate the ones you plan to support. (to activate a
+currency, check his active field)
+
+After having activated the currencies, you can configure the parameters
+to automate the currency rate update. These options are also in the
+settings of the Accounting application, in the bottom of the page:
+
+.. image:: media/foreign01.png
+   :align: center
+
+Click on the **Update Now** link to update the currency rates now.
+
+Create a new bank account
+-------------------------
+
+In the accounting application, we first go to :menuselection:`Configuration -->
+Accounting / Bank account`, and we create a new one.
+
+.. image:: media/foreign02.png
+   :align: center
+
+Once you save this bank account, Odoo will create all the documents for
+you:
+
+- An account in the trial balance
+
+- A journal in your dashboard
+
+- Information about the bank account in the footer of your invoices if
+  checked the box **Show in Invoices Footer**
+
+Example: A vendor bill in a foreign currency
+============================================
+
+Based on the above example, let's assume we receive the following bill
+from a supplier in China.
+
+In the :menuselection:`Purchase --> Vendor Bills` , this is what you could see:
+
+.. image:: media/foreign03.png
+   :align: center
+
+Once you are ready to pay this bill, click on register payment on the
+bill to record a payment.
+
+.. image:: media/foreign04.png
+   :align: center
+
+That's all you have to do. Odoo will automatically post the foreign
+exchange gain or loss at the reconciliation of the payment with the
+invoice, depending if the currency rate increased or decreased between
+the invoice and the payment date.
+
+Note that you can pay a foreign bill with another currency. In such a
+case, Odoo will automatically convert between the two currencies.
+
+Customers Statements
+====================
+
+Customers and vendor statements are managed in the currency of the
+invoice. So, the amount due by your customer (to your vendor) is always
+expressed in the currency of the invoice.
+
+If you have several invoices with different currencies for the same
+customer, Odoo will split the customer statement by currency, as shown
+in the report below.
+
+.. image:: media/foreign05.png
+   :align: center
+
+In the above report, the account receivable associated to Camptocamp is
+not managed in a secondary currency, which means that it keeps every
+transaction in his own currency. If you prefer, you can set the account
+receivable of this customer with a secondary currency and all his debts
+will automatically be converted in this currency.
+
+In such a case, the customer statement always has only one currency. In
+general, this is not what the customer expect as he prefers to see the
+amounts in the currency of the invoices he received;