Feature: Knowledge Base APIs (#1002)

- Introduce models & migrations for portals, categories, folders and articles
- CRUD API for portals
- CRUD API for categories

Addresses: #714

Co-authored-by: Sojan <sojan@pepalo.com>

config/routes.rb

@@ -98,6 +98,15 @@ Rails.application.routes.draw do
             resources :apps, only: [:index, :show]
             resource :slack, only: [:create, :update, :destroy], controller: 'slack'
           end
+
+          namespace :kbase do
+            resources :portals do
+              resources :categories do
+                resources :folders
+              end
+              resources :articles
+            end
+          end
         end
       end
       # end of account scoped api routes