基本功能完成，下一步开始美化UI

.opencode/300-database/schema.yaml

@@ -28,6 +28,50 @@ database:
         - name: "idx_users_created_at"
           columns: ["created_at"]
 
+    - name: "user_groups"
+      columns:
+        - name: "id"
+          type: "TEXT"
+          primaryKey: true
+        - name: "name"
+          type: "TEXT"
+          nullable: false
+          unique: true
+        - name: "description"
+          type: "TEXT"
+        - name: "is_system"
+          type: "INTEGER"
+          default: "0"
+          comment: "是否为系统内置组 (0:否, 1:是)"
+        - name: "created_at"
+          type: "DATETIME"
+          default: "CURRENT_TIMESTAMP"
+      indexes:
+        - name: "idx_user_groups_name"
+          columns: ["name"]
+
+    - name: "user_group_members"
+      columns:
+        - name: "group_id"
+          type: "TEXT"
+          nullable: false
+          foreignKey:
+            table: "user_groups"
+            column: "id"
+        - name: "user_id"
+          type: "TEXT"
+          nullable: false
+          foreignKey:
+            table: "users"
+            column: "id"
+        - name: "created_at"
+          type: "DATETIME"
+          default: "CURRENT_TIMESTAMP"
+      indexes:
+        - name: "idx_user_group_members_unique"
+          columns: ["group_id", "user_id"]
+          unique: true
+
     - name: "question_categories"
       columns:
         - name: "id"