def edit
      @comment = @commentable.comments.find(params[:id])
    end

    def update
       @comment.update!(comment_params)
       redirect_back(fallback_location: root_url)
       render "edit"
    end

<%= link_to 'Edit', [:edit, comment.commentable, comment] %>

class Comment < ApplicationRecord


  after_commit :create_notifications, on: :create

  belongs_to :commentable, polymorphic: true
  has_many :comments, as: :commentable
  belongs_to :user, optional: true

  validates :body, presence: true

  def deleted?
    user.nil?
  end

  private

  def create_notifications
   Notification.create do |notification|
     notification.notify_type = 'commentable'
     notification.actor = self.user
     notification.user = self.commentable.user
     notification.target = self
     notification.second_target = self.commentable
   end
 end

end

<div class=''>
  <%= link_to notification.actor.email, main_app.user_path(notification.actor) %> has commented in

</div>

<div class=''>
  <%= notification.target.body %>
</div>