When using Rails strong parameters feature to permit certain parameters in controller and if any specific param has array values, we need to permit it as an array explicitly

Eg:
Request: /api/v1/calendar.json?date_from=&date_to=&hotel_id[]=1&hotel_id[]=2

def permit_params
  params.permit(:date_from, :date_to, hotel_id: []) # hotel_id: [] is important
end