ADD model ProjectCategory

app/models/project.rb

@@ -42,7 +42,8 @@ class Project < ActiveRecord::Base
       indexes :updated_on, index:"not_analyzed", type:'date'
     end
   end
-
+  
+  belongs_to :project_category , :counter_cache => true
   has_many :student_work_projects, :dependent => :destroy
   has_many :contestant_work_projects, :dependent => :destroy
   has_many :student_works

app/models/project_category.rb

@@ -0,0 +1,6 @@
+# 项目类别
+class ProjectCategory < ActiveRecord::Base
+  attr_accessible :name, :position, :projects_count
+
+  has_many :projects
+end

db/migrate/20191107015025_create_project_categories.rb

@@ -0,0 +1,15 @@
+class CreateProjectCategories < ActiveRecord::Migration
+  def change
+    create_table :project_categories do |t|
+      t.string :name
+      t.integer :position
+      t.integer :projects_count, :default => 0
+
+      t.timestamps
+    end
+    names = %w(大数据 机器学习 深度学习 人工智能 量子计算 智慧医疗 自动驾驶 其他)
+    names.each do |name|
+      ProjectCategory.where(name: name).first_or_create
+    end
+  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 => 20191026085118) do
+ActiveRecord::Schema.define(:version => 20191107015025) do
 
   create_table "activities", :force => true do |t|
     t.integer  "act_id",                                  :null => false
@@ -1974,6 +1974,14 @@ ActiveRecord::Schema.define(:version => 20191026085118) do
     t.datetime "updated_at", :null => false
   end
 
+  create_table "project_categories", :force => true do |t|
+    t.string   "name"
+    t.integer  "position"
+    t.integer  "projects_count", :default => 0
+    t.datetime "created_at",                    :null => false
+    t.datetime "updated_at",                    :null => false
+  end
+
   create_table "project_infos", :force => true do |t|
     t.integer  "project_id"
     t.integer  "user_id"