Merge pull request '为建站主题配置增加删除限制' (#126) from KingChan/forgeplus:chenjing into standalone_develop

app/controllers/admins/page_themes_controller.rb

@@ -30,6 +30,11 @@ class Admins::PageThemesController <   Admins::BaseController
     end
 
     def destroy
+        if PageTheme.where(language_frame: @page_theme.language_frame).count <= 1
+            flash[:danger] = "删除主题失败,必须存在一个主题"
+            return redirect_to admins_page_themes_path
+        end
+        
         if @page_theme.destroy 
             redirect_to admins_page_themes_path
             flash[:success] = "删除主题成功"