* Circle.cs:

* CircleInfo.cs:
* CircleInfoCollection.cs: cleans imports

* CircleManager.cs: implements a circle manager

* CircleProvider.cs: Defines a default Circle provider

* EventPub.cs:
* CalendarController.cs: refactoring

* CircleController.cs: implements with default circle provider

* FrontOfficeController.cs: throws descriptive exception message at
  searching for a catalog

* Catalog.aspx: Fixes links on product categories

* ProductCategory.aspx: Fixes links on products

* YavscModel.csproj: Includes Circle provider definitions

web/ApiControllers/CalendarController.cs

@@ -26,6 +26,7 @@ using System.Web.Security;
 using Yavsc.Model.Google;
 using Yavsc.Helpers;
 using System.Web.Profile;
+using Yavsc.Model.Circles;
 
 
 namespace Yavsc.ApiControllers

web/ApiControllers/CircleController.cs

@@ -20,6 +20,10 @@
 //  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 using System;
 using System.Web.Http;
+using Yavsc.Model.RolesAndMembers;
+using System.Collections.Generic;
+using Yavsc.Model.Circles;
+using System.Web.Security;
 
 namespace Yavsc.ApiControllers
 {
@@ -32,26 +36,44 @@ namespace Yavsc.ApiControllers
 		/// Add the specified id and users.
 		/// </summary>
 		/// <param name="id">Identifier.</param>
+		/// <param name="title">Title.</param>
 		/// <param name="users">Users.</param>
+		[Authorize]
 		public void Add(string id, string [] users) 
 		{
-			throw new NotImplementedException ();
+			string user = Membership.GetUser ().UserName;
+			CircleManager.DefaultProvider.Add (user, id, users);
 		}
 		/// <summary>
 		/// Delete the specified id.
 		/// </summary>
 		/// <param name="id">Identifier.</param>
-		public void Delete(string id) 
+		[Authorize] public void Delete(string id) 
 		{
-			throw new NotImplementedException ();
+			string user = Membership.GetUser ().UserName;
+			CircleManager.DefaultProvider.Delete (user, id);
 		}
+
 		/// <summary>
 		/// Get the specified id.
 		/// </summary>
 		/// <param name="id">Identifier.</param>
-		public string[] Get(string id)
+		[Authorize]
+		public Circle Get(string id)
 		{
-			throw new NotImplementedException ();
+			string user = Membership.GetUser ().UserName;
+			return CircleManager.DefaultProvider.Get (user, id);
+		}
+
+
+		/// <summary>
+		/// List this instance.
+		/// </summary>
+		[Authorize]
+		public CircleInfoCollection List()
+		{
+			string user = Membership.GetUser ().UserName;
+			return CircleManager.DefaultProvider.List ();
 		}
 	}
 }