class AddHintsToComponents < ActiveRecord::Migration[5.0]

  def change

    add_column :components, :hints, :text

  end

end

  def update

    if @component.update!(component_params)

      redirect_to @component, notice: 'Component was successfully updated.'

    else

      render :error

    end

  end 

    def component_params

      params.require(:component).permit(:release_id,

                                        :remark, component_ids: [], hints: [:left, :mid, :right])

    end

class Component < ApplicationRecord

  serialize :hints

  def after_initialize

      self.hints ||= {}

  end

  <td>

    left:<%= component.hints["left"] %> |

    mid:<%= component.hints["mid"] %> |

    right:<%= component.hints["right"] %>

  </td

  <%= f.fields_for :hints do |h| %>

    <div class="form-group">

      <%= f.label 'hints left', class: 'col-sm-2 control-label' %>

      <div class="col-sm-4">

        <%= h.text_field :left, class: 'form-control',

          value: (@component.hints && @component.hints.key?("left") ? @component.hints["left"] : "") %>

      </div>

    </div>

    <div class="form-group">

      <%= f.label 'hints mid', class: 'col-sm-2 control-label' %>

      <div class="col-sm-4">

        <%= h.text_field :mid, class: 'form-control',

          value: (@component.hints && @component.hints.key?("mid") ? @component.hints["mid"] : "") %>

      </div>

    </div>

    <div class="form-group">

      <%= f.label 'hints right', class: 'col-sm-2 control-label' %>

      <div class="col-sm-4">

        <%= h.text_field :right, class: 'form-control',

          value: (@component.hints && @component.hints.key?("right") ? @component.hints["right"] : "") %>

      </div>

    </div>

  <% end %>