Added Observable classes and got started on observable tests

Octokit/Clients/UserAdministrationClient.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Octokit.Clients
+{
+    public class UserAdministrationClient : ApiClient, IUserAdministrationClient
+    {
+        public UserAdministrationClient(IApiConnection apiConnection)
+            : base(apiConnection)
+        {
+        }
+
+        public Task Demote(string login)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Task Promote(string login)
+        {
+            Ensure.ArgumentNotNullOrEmptyString(login, "login");
+            var endpoint = ApiUrls.UserAdministration(login);
+
+            return ApiConnection.Put(endpoint);
+        }
+
+        public Task Suspend(string login)
+        {
+            throw new NotImplementedException();
+        }
+
+        public Task Unsuspend(string login)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}