added groups apis

src/Core/Models/Api/Response/GroupResponseModel.cs

@@ -0,0 +1,25 @@
+using System;
+using Bit.Core.Models.Table;
+
+namespace Bit.Core.Models.Api
+{
+    public class GroupResponseModel : ResponseModel
+    {
+        public GroupResponseModel(Group group, string obj = "group")
+            : base(obj)
+        {
+            if(group == null)
+            {
+                throw new ArgumentNullException(nameof(group));
+            }
+
+            Id = group.Id.ToString();
+            OrganizationId = group.OrganizationId.ToString();
+            Name = group.Name;
+        }
+
+        public string Id { get; set; }
+        public string OrganizationId { get; set; }
+        public string Name { get; set; }
+    }
+}