[ADD] accounting: How to track costs of human resources with timesheets?

https://docs.google.com/document/d/1QbHvzVFTzF5YWRTFq02PgRCuTQ2kmYvYcNjm3ahGkIc/edit#heading=h.9gsk2r5sj3ql

accounting/others/analytic/timesheets.rst

@@ -1,3 +1,173 @@
 ========================================================
-How to track costs of human resources with timesheets?
-========================================================
+How to track costs of human resources with timesheets ?
+========================================================
+
+Human resource of course has a cost. It is interesting to see how much a
+particular contract costs the company in term of human power in relation
+to the invoiced amounts.
+
+We will take the following example: Our two employees **Harry Potter** and
+**Cedric Digory** both work on a **Consultancy pack** for our customer
+**Smith&Co**. Harry is paid 18€ p.h. and Cedric's salary is 12€ p.h. We
+would like to track their timesheet costs within the accounting app, and
+compare them with the revenue of the consultancy service.
+
+Configuration
+=============
+
+First, install the three applications necessary to use this
+functionality, namely **Accounting**, **Sales** and **Timesheet**. Enter the apps
+module name and install them.
+
+.. image:: media/timesheets14.png  
+   :align: center
+
+.. image:: media/timesheets05.png
+   :align: center
+
+.. image:: media/timesheets11.png
+   :align: center
+
+Next you will need to enable analytical accounting. To do so enter the
+**Accounting app**. Select :menuselection:`Configuration --> Settings` and tick the
+**Analytic accounting** option (see picture below)
+
+.. image:: media/timesheets06.png
+   :align: center
+
+Apply your changes.
+
+Create an employee
+------------------
+
+In order to check the revenue of an employee you need to have one. To
+create an employee enter the **Employee** app. Select **Employees** and
+create a new employee, fill in the name and the basic information.
+
+On the employee sheet enter the **HR settings** tab. Here you are able to
+specify the **Timesheet Cost** of your employee. In this case Harry has a
+cost of 18 euros / hours. We will thus fill in 18 in this field.
+
+.. image:: media/timesheets07.png
+   :align: center
+
+.. note:: 
+    If you want the employee to be able to enter timesheets he
+    needs to be related to a User.
+
+Repeat the operation to create the Cedric Digory employee. Don't forget
+to specify its related user and **Timesheet Costs**.
+
+Issue a Sales Order 
+--------------------
+
+We created two employees called Harry Potter and Cedric Diggory in the
+**Employee** app. Both of them will work on a consultancy contract for our
+customer Smith&Co where they will point their hours on a timesheet.
+
+We thus need to create a **sales order** with a **service** product invoiced
+**based on time and material** and tracked by timesheets with **hours** as unit
+of measures.
+
+.. image:: media/timesheets03.png
+   :align: center
+
+For more information on how to create a sales order based on time and
+material please see: *How to invoice based on time and material* (Work in Progress).
+
+.. todo::
+    Add a link, and the document is under 
+    Sales --> Invoicing Methods --> Services --> How to invoices blabla
+
+We save a Sales Order with the service product **External Consulting**. An
+analytical account will automatically be generated once the **Sales Order**
+is confirmed. Our employees will have to point to that account (in this
+case **SO002-Smith&Co**) in order to be able to invoice their hours (see
+picture below).
+
+.. image:: media/timesheets10.png
+   :align: center
+
+Fill in timesheet
+-----------------
+
+As an employee linked to a user, Harry can enter the **Timesheet** app and
+specify his timesheets for the contract. Logged on Harry's account we enter the
+**Timesheet** app and enter a detailed line pointing to the **Analytical
+Account** discussed above.
+
+Harry worked three hours on a SWOT analysis for Smith&Co.
+
+.. image:: media/timesheets01.png
+   :align: center
+
+In the meantime, Cedric discussed businesses needs with the customer for
+1 hour and specified it as well in his personal timesheet, pointing as
+well on the **Analytic Account**.
+
+In the **Sales Order** we notice that the delivered amounts of hours is
+automatically computed (see picture below).
+
+.. image:: media/timesheets02.png
+   :align: center
+
+Analytic accounting
+-------------------
+
+Thanks to analytic accounts we are able to have an overview of HR cost
+and revenues. All the revenues and cost of this transactions have been
+registered in the **SO002-Smith&Co** account.
+
+We can use two methods to analyze this situation.
+
+Without filters
+~~~~~~~~~~~~~~~
+
+If we pointed all our costs and revenues of the project on the correct
+analytical account we can easily retrieve the cost and revenues related
+to this analytical account. Enter the *Accounting* app, select 
+:menuselection:`Adviser --> Analytic Accounts --> Open Charts`.
+
+Note : you can specify a period for **Analysis**. If you want to open the
+current situation you should keep the fields empty. We can already note
+the credit and debit balance of the account.
+
+.. image:: media/timesheets12.png
+   :align: center
+
+If we click on the account a special button is provided to have the
+details of cost and revenues (see picture below).
+
+.. image:: media/timesheets13.png
+   :align: center
+
+Click the button **Cost/Revenue** to have an overview of cost and revenues with the
+corresponding description.
+
+With filters
+~~~~~~~~~~~~
+
+We can thus filter this information from the **Analytic Entries**.
+
+Enter the **Accounting** app, and click on :menuselection:`Adviser --> Analytic Entries`.
+In this menu we have several options to analyse the human resource cost.
+
+1. We filter on the **Analytic account** so we can see the cost and revenues
+   of the project. Add a custom **Filter** where the **Analytic Account**
+   contains the **Sales Order** number.
+
+   .. image:: media/timesheets04.png
+      :align: center
+
+   In the results we see timesheets activities and invoiced lines with
+   the corresponding costs and revenues.
+
+   .. image:: media/timesheets09.png
+     :align: center
+
+2. We can group the different analytical accounts together and check
+   their respective revenues. Simply group by **Analytic account** and
+   select the **Graph view** to have a clear overview.
+
+   .. image:: media/timesheets08.png
+      :align: center