feat: APIs for Articles (#4777)

Fixes: #4802

app/models/category.rb

@@ -2,20 +2,22 @@
 #
 # Table name: categories
 #
-#  id          :bigint           not null, primary key
-#  description :text
-#  locale      :string           default("en")
-#  name        :string
-#  position    :integer
-#  created_at  :datetime         not null
-#  updated_at  :datetime         not null
-#  account_id  :integer          not null
-#  portal_id   :integer          not null
+#  id                        :bigint           not null, primary key
+#  description               :text
+#  locale                    :string           default("en")
+#  name                      :string
+#  position                  :integer
+#  slug                      :string           not null
+#  created_at                :datetime         not null
+#  updated_at                :datetime         not null
+#  account_id                :integer          not null
+#  portal_id                 :integer          not null
 #
 # Indexes
 #
-#  index_categories_on_locale                 (locale)
-#  index_categories_on_locale_and_account_id  (locale,account_id)
+#  index_categories_on_locale                         (locale)
+#  index_categories_on_locale_and_account_id          (locale,account_id)
+#  index_categories_on_slug_and_locale_and_portal_id  (slug,locale,portal_id) UNIQUE
 #
 class Category < ApplicationRecord
   belongs_to :account
@@ -25,7 +27,20 @@ class Category < ApplicationRecord
 
   before_validation :ensure_account_id
   validates :account_id, presence: true
+  validates :slug, presence: true
   validates :name, presence: true
+  validates :locale, uniqueness: { scope: %i[slug portal_id],
+                                   message: 'should be unique in the category and portal' }
+
+  scope :search_by_locale, ->(locale) { where(locale: locale) if locale.present? }
+
+  def self.search(params)
+    search_by_locale(params[:locale]).page(current_page(params)).order(position: :asc)
+  end
+
+  def self.current_page(params)
+    params[:page] || 1
+  end
 
   private