Handle post request.

def post(self):
    """Handle post request."""
    client_customer_id = self.request.get('clientCustomerId')
    budget_id = self.request.get('budgetId')
    if not client_customer_id or not budget_id:
      self.redirect('/')
    else:
      self.redirect('/showBudget?clientCustomerId=%s&budgetId=%s'
                    % (client_customer_id, budget_id))