[IMP] fleet: Display all the stages on the fleet.vehicle kanban view

All the stage should be displayed to allow a user to move a car in another stage
even if no other cars are into it.

addons/fleet/models/fleet_vehicle.py

@@ -35,7 +35,8 @@ class FleetVehicle(models.Model):
     acquisition_date = fields.Date('Immatriculation Date', required=False,
         default=fields.Date.today, help='Date when the vehicle has been immatriculated')
     color = fields.Char(help='Color of the vehicle')
-    state_id = fields.Many2one('fleet.vehicle.state', 'State', default=_get_default_state, 
+    state_id = fields.Many2one('fleet.vehicle.state', 'State',
+        default=_get_default_state, group_expand='_read_group_stage_ids',
         help='Current state of the vehicle', ondelete="set null")
     location = fields.Char(help='Location of the vehicle (garage, ...)')
     seats = fields.Integer('Seats Number', help='Number of seats of the vehicle')
@@ -223,6 +224,10 @@ class FleetVehicle(models.Model):
 
             return super(FleetVehicle, self).write(vals)
 
+    @api.model
+    def _read_group_stage_ids(self, stages, domain, order):
+        return self.env['fleet.vehicle.state'].search([], order=order)
+
     @api.multi
     def return_action_to_open(self):
         """ This opens the xml view specified in xml_id for the current vehicle """

addons/fleet/views/fleet_vehicle_views.xml

@@ -227,6 +227,7 @@
         <field name="res_model">fleet.vehicle</field>
         <field name="view_type">form</field>
         <field name="view_mode">kanban,tree,form</field>
+        <field name="context">{'search_default_groupby_status': 1}</field>
         <field name="help" type="html">
           <p class="o_view_nocontent_smiling_face">
             Create a new vehicle