[ADD] Accounting: How to register customer payments by checks ?

https://docs.google.com/document/d/1ZRHMaaVvrjEZn27UTYC9eUL5T03WYOUqRE-ye2hvCQ8/edit#heading=h.rnc4w7jho1pm

accounting/receivables/customer_payments/check.rst

@@ -1,3 +1,151 @@
-==================================
-How to record a payment by checks?
-==================================
+============================================
+How to register customer payments by checks
+============================================
+
+There are two ways to handle payments received by checks. Odoo support
+both approaches so that you can use the one that better fits your
+habits.
+
+1. **Undeposited Funds:** 
+   once you receive the check, you record a payment
+   by check on the invoice. (using a Check journal and posted on the
+   Undeposited Fund account) Then, once the check arrives in your
+   bank account, move money from Undeposited Funds to your bank
+   account.
+
+2. **One journal entry only:** 
+   once your receive the check, you record a
+   payment on your bank, paid by check, without going through the
+   **Undeposited Funds**. Once you process your bank statement, you do
+   the matching with your bank feed and the check payment, without
+   creating a dedicated journal entry.
+
+We recommend the first approach as it is more accurate (your bank
+account balance is accurate, taking into accounts checks that have not
+been cashed yet). Both approaches require the same effort.
+
+Even if the first method is cleaner, Odoo support the second approach
+because some accountants are used to it (quickbooks and peachtree
+users).
+
+.. Note:: 
+  You may have a look at the *Deposit Ticket feature* if you deposit
+  several checks to your bank accounts in batch.
+
+Option 1: Undeposited Funds
+===========================
+
+Configuration
+-------------
+
+-  Create a journal **Checks**
+
+-  Set **Undeposited Checks** as a defaut credit/debit account
+
+-  Set the bank account related to this journal as **Allow Reconciliation**
+
+From check payments to bank statements
+--------------------------------------
+
+The first way to handle checks is to create a check journal. Thus,
+checks become a payment method in itself and you will record two
+transactions.
+
+Once you receive a customer check, go to the related invoice and click
+on **Register Payment**. Fill in the information about the payment:
+
+-  Payment method: Check Journal (that you configured with the debit and
+   credit default accounts as **Undeposited Funds**)
+
+-  Memo: write the Check number
+
+.. image:: ./media/check01.png
+  :align: center
+
+This operation will produce the following journal entry:
+
++----------------------+-------------------+----------+----------+
+| Account              | Statement Match   | Debit    | Credit   |
++======================+===================+==========+==========+
+| Account Receivable   |                   |          | 100.00   |
++----------------------+-------------------+----------+----------+
+| Undeposited Funds    |                   | 100.00   |          |
++----------------------+-------------------+----------+----------+
+
+The invoice is marked as paid as soon as you record the check.
+
+Then, once you get the bank statements, you will match this statement
+with the check that is in Undeposited Funds.
+
++---------------------+-------------------+----------+----------+
+| Account             | Statement Match   | Debit    | Credit   |
++=====================+===================+==========+==========+
+| Undeposited Funds   | X                 |          | 100.00   |
++---------------------+-------------------+----------+----------+
+| Bank                |                   | 100.00   |          |
++---------------------+-------------------+----------+----------+
+
+
+If you use this approach to manage received checks, you get the list of
+checks that have not been cashed in the **Undeposit Funds** account
+(accessible, for example, from the general ledger).
+
+.. Note:: 
+    Both methods will produce the same data in your accounting at the
+    end of the process. But, if you have checks that have not been cashed,
+    this one is cleaner because those checks have not been reported yet on
+    your bank account.
+
+Option 2: One journal entry only
+================================
+
+Configuration
+-------------
+
+These is nothing to configure if you plan to manage your checks using
+this method.
+
+From check payments to bank statements
+--------------------------------------
+
+Once you receive a customer check, go to the related invoice and click
+on **Register Payment**. Fill in the information about the payment:
+
+-  **Payment method:** the bank that will be used for the deposit
+
+-  Memo: write the check number
+
+.. image:: ./media/check02.png
+  :align: center
+
+The invoice is marked as paid as soon as you record the check.
+
+Once you will receive the bank statements, you will do the matching with
+the statement and this actual payment. (technically: point this payment
+and relate it to the statement line)
+
+With this approach, you will get the following journal entry in your
+books:
+
++----------------------+-------------------+----------+----------+
+| Account              | Statement Match   | Debit    | Credit   |
++======================+===================+==========+==========+
+| Account Receivable   | X                 |          | 100.00   |
++----------------------+-------------------+----------+----------+
+| Bank                 |                   | 100.00   |          |
++----------------------+-------------------+----------+----------+
+
+.. tip:: 
+    You may also record the payment directly without going on the
+    customer invoice, using the menu :menuselection:`Sales --> Payments`. This method may
+    be more convenient if you have a lot of checks to record in a batch but
+    you will have to reconcile entries afterwards (matching payments with
+    invoices)
+
+If you use this approach to manage received checks, you can use the
+report **Bank Reconciliation Report** to verify which checks have been
+received or paid by the bank. (this report is available from the **More**
+option from the Accounting dashboard on the related bank account).
+
+.. image:: ./media/check03.png
+  :align: center