给应用添加图标，完成给设备添加变量表的功能

Data/Repositories/MenuRepository.cs

@@ -40,7 +40,7 @@ public class MenuRepository
     }
 
 
-    public async Task<int> AddMenu(MenuBean menu)
+    public async Task<int> Add(MenuBean menu)
     {
         using (var db = DbContext.GetInstance())
         {

Data/Repositories/VarTableRepository.cs

@@ -0,0 +1,21 @@
+using PMSWPF.Data.Entities;
+using PMSWPF.Extensions;
+using PMSWPF.Models;
+
+namespace PMSWPF.Data.Repositories;
+
+public class VarTableRepository
+{
+    /// <summary>
+    /// 添加变量表
+    /// </summary>
+    /// <param name="varTable"></param>
+    /// <returns>变量表的ID</returns>
+    public async Task<int> Add(VariableTable varTable)
+    {
+        using (var db = DbContext.GetInstance())
+        {
+            return await db.Insertable<DbVariableTable>(varTable.CopyTo<DbVariableTable>()).ExecuteReturnIdentityAsync();
+        }
+    }
+}