best_in_place
method takes two mandatory arguments; an object (shift
in you case) and a field (shiftstart
and shiftend
), then optional hash of options (:type => :input
). So your code needs to be like this:
<%= best_in_place shift, :shiftstart, :type => :input, :display_with => Proc.new { |f| f.strftime("%H.%M") } %>