ADD a tree structure to model ProjectCategory

Gemfile

@@ -51,6 +51,8 @@ gem 'kaminari'
 gem 'elasticsearch-model'
 gem 'elasticsearch-rails'
 
+gem 'ancestry'
+
 #rails 3.2.22.2 bug
 # gem "test-unit", "~>3.0"
 

app/models/project_category.rb

@@ -1,6 +1,7 @@
 # 项目类别
 class ProjectCategory < ActiveRecord::Base
   attr_accessible :name, :position, :projects_count
+  has_ancestry
 
   has_many :projects
 end

db/migrate/20191107031711_add_ancestry_to_project_categories.rb

@@ -0,0 +1,6 @@
+class AddAncestryToProjectCategories < ActiveRecord::Migration
+  def change
+    add_column :project_categories, :ancestry, :string
+    add_index :project_categories, :ancestry
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20191107015025) do
+ActiveRecord::Schema.define(:version => 20191107031711) do
 
   create_table "activities", :force => true do |t|
     t.integer  "act_id",                                  :null => false
@@ -1980,8 +1980,11 @@ ActiveRecord::Schema.define(:version => 20191107015025) do
     t.integer  "projects_count", :default => 0
     t.datetime "created_at",                    :null => false
     t.datetime "updated_at",                    :null => false
+    t.string   "ancestry"
   end
 
+  add_index "project_categories", ["ancestry"], :name => "index_project_categories_on_ancestry"
+
   create_table "project_infos", :force => true do |t|
     t.integer  "project_id"
     t.integer  "user_id"