add limit of post per day

app/models/post.rb

@@ -5,6 +5,8 @@ class Post < ApplicationRecord
   validates :content, length: { maximum: 777 }
   validates :content, presence: true, if: :quoted_post?
 
+  validate :user, :limit_of_post_per_day
+
   def kind
     if quoted_post?
       :quoted_post
@@ -24,4 +26,12 @@ class Post < ApplicationRecord
   def repost?
     content.blank? && quoted_post_id
   end
+
+  def limit_of_post_per_day
+    posts_from_day = user.posts.where('created_at >= ?', Time.zone.now.beginning_of_day)
+
+    if posts_from_day.count >= 5
+      errors.add(:base, 'You can post only 5 posts per day')
+    end
+  end
 end