authentication API

# This is how I improve this rails action
# authentication API
def auth
  # find is a method to search by id use find_by if we use other field as parameter
  # declare user as a class method
  @user = User.find_by(username: params[:username])

  # Before we check the password,
  # We need to check if the user with that username is present
  if @user.present? && @user.check_password(params[:password])
    # json response should always including status
    # give status ok (200) for successful auth
    render json: @user, status: :ok
  else
    # The errors message is not needed to be in an array
    # Use single-quoted if we don't use string interpolation.
    render json: { errors: 'wrong username or password' }, status: :unauthorized
  end
end