feat: Category API to handle linked categories and parent-sub categories (#4879)

app/views/api/v1/accounts/categories/_associated_category.json.jbuilder

@@ -0,0 +1,7 @@
+json.id category.id
+json.name category.name
+json.slug category.slug
+json.locale category.locale
+json.description category.description
+json.position category.position
+json.account_id category.account_id

app/views/api/v1/accounts/categories/_category.json.jbuilder

@@ -5,3 +5,23 @@ json.locale category.locale
 json.description category.description
 json.position category.position
 json.account_id category.account_id
+
+json.related_categories do
+  if category.related_categories.any?
+    json.array! category.related_categories.each do |related_category|
+      json.partial! 'api/v1/accounts/categories/associated_category.json.jbuilder', category: related_category
+    end
+  end
+end
+
+if category.parent_category.present?
+  json.parent_category do
+    json.partial! 'api/v1/accounts/categories/associated_category.json.jbuilder', category: category.parent_category
+  end
+end
+
+if category.linked_category.present?
+  json.linked_category do
+    json.partial! 'api/v1/accounts/categories/associated_category.json.jbuilder', category: category.linked_category
+  end
+end

app/views/api/v1/accounts/categories/show.json.jbuilder

@@ -0,0 +1,3 @@
+json.payload do
+  json.partial! 'category', category: @category
+end