Simple notification function in Rails (only when followed)

A simple notification feature in Rails. (Only when followed for the time being)

Routing settings

config/routes.rb

  resources :notifications, only: [:index]

Creating a controller

$ rails g controller notifications

Creating a model

$ rails g model Notification visitor_id:integer visited_id:integer

$ rails db:migrate

Model and association settings

app/models/user.rb

  has_many :active_notifications, class_name: "Notification", foreign_key: "visitor_id", dependent: :destroy
  has_many :passive_notifications, class_name: "Notification", foreign_key: "visited_id", dependent: :destroy

  def create_notification_follow!(current_user)
    temp = Notification.where(["visitor_id = ? and visited_id = ? ",current_user.id, id])
    if temp.blank?
      notification = current_user.active_notifications.new(visited_id: id)
      notification.save if notification.valid?
    end
  end

app/models/notification.rb

  belongs_to :visitor, class_name: 'User', foreign_key: 'visitor_id'
  belongs_to :visited, class_name: 'User', foreign_key: 'visited_id'

Controller settings

app/controllers/relationships_controller.rb

  def create
    @user = User.find(params[:user_id])
    current_user.follow(params[:user_id])
    @user.create_notification_follow!(current_user) #Postscript part
    redirect_to request.referer
  end

app/controllers/notifications_controller.rb

  def index
    @notifications = current_user.passive_notifications.order(created_at: :DESC)
  end

View (notification list) settings

app/views/notifications/index.html

<h1>Notice</h1>
<% if @notifications.exists? %>
  <% @notifications.each do |notification| %>
    <table>
      <tr>
        <td>
          <%= attachment_image_tag notification.visitor, :image, size: "50x50" %>
        </td>
        <td>
          <%= link_to user_path(notification.visitor) do %>
            <%= notification.visitor.name %>
          <% end %>
        </td>
        <td>
Followed by.
        </td>
        <td>
          <%= " (#{time_ago_in_words(notification.created_at)}Before)" %>
        </td>
      </tr>
    </table>
  <% end %>
<% else %>
  <p>There is no news</p>
<% end %>