How to extend the Content Editor

Hello,

In training materials it's shown a possibility to extend the editor:
https://community.telligent.com/community/11/w/developer-training/65057/extending-the-content-editor

I'm trying to do the same (at least to repeat the sample) without any success. Could you help to identify missings?

Extensions/Controllers/TextEditor.cs

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using Telligent.DynamicConfiguration.Components;
using Telligent.Evolution.Extensibility.EmbeddableContent.Version1;
using Telligent.Evolution.Extensibility.Version1;

namespace Test.Extensions.Controllers
{
	public class TextEditor : IEmbeddableContentFragmentType, ITranslatablePlugin, IPlugin
	{
		readonly Guid _fragmentTypeId = new Guid("6c33babb0c0e45e8b691294b8b6569e5");

		ITranslatablePluginController _translation;

		#region IEmbeddableContentFragmentType Members
		public string ContentFragmentName
		{
			get { return _translation.GetLanguageResourceValue("fragment_name"); }
		}

		public string ContentFragmentDescription
		{
			get { return _translation.GetLanguageResourceValue("fragment_description"); }
		}

		public Guid EmbeddedContentFragmentTypeId
		{
			get { return _fragmentTypeId; }
		}

		public bool CanEmbed(Guid contentTypeId, int userId)
		{
			return true;
		}

		PropertyGroup[] IEmbeddableContentFragmentType.EmbedConfiguration
		{
			get
			{
				var group = new PropertyGroup("options", _translation.GetLanguageResourceValue("configuration_group"), 1);
				group.Properties.Add(new Property("color", _translation.GetLanguageResourceValue("configuration_color"), PropertyType.Color, 1, ""));
				return new PropertyGroup[] { group };
			}
		}

		void IEmbeddableContentFragmentType.AddUpdateContentFragments(Guid contentId, Guid contentTypeId, IEnumerable<IEmbeddableContentFragment> embeddedFragments)
		{

		}

		public string PreviewImageUrl
		{
			get { return null; }
		}

		string IEmbeddableContentFragmentType.Render(IEmbeddableContentFragment embeddedFragment, string target)
		{
			if (System.Diagnostics.Debugger.Launch()) System.Diagnostics.Debugger.Break();

			var color = embeddedFragment.GetString("color");

			if (String.IsNullOrEmpty(color))
				return String.Empty;

			return String.Format("<div style='height: 300px; width: 300px; background-color: {0};'> </div>", color);
		}

		EmbeddableContentFragmentValidationState IEmbeddableContentFragmentType.Validate(IEmbeddableContentFragment embeddedFragment)
		{
			if (System.Diagnostics.Debugger.Launch()) System.Diagnostics.Debugger.Break();

			var color = embeddedFragment.GetString("color");

			if (string.IsNullOrEmpty(color))
				return new EmbeddableContentFragmentValidationState(false) { Message = _translation.GetLanguageResourceValue("configuration_colorinvalid") };

			return new EmbeddableContentFragmentValidationState(true);
		}
		#endregion

		#region IPlugin Members
		string IPlugin.Description
		{
			get { return "Displays a box with configurable height."; }
		}

		void IPlugin.Initialize()
		{

		}

		string IPlugin.Name
		{
			get { return "Sample Embeddable"; }
		}
		#endregion

		#region ITranslatablePlugin Members
		Translation[] ITranslatablePlugin.DefaultTranslations
		{
			get
			{
				var translation = new Translation("en-us");

				translation.Set("fragment_name", "Embeddable Box");
				translation.Set("fragment_description", "Displays a box with configurable height.");

				translation.Set("configuration_group", "Options");
				translation.Set("configuration_color", "Background Color");
				translation.Set("configuration_colorinvalid", "A Background Color must be provided.");

				return new Translation[] { translation };
			}
		}

		void ITranslatablePlugin.SetController(ITranslatablePluginController controller)
		{
			_translation = controller;
		}
		#endregion
	}
}

	public class TextEditorExtension : IScriptedContentFragmentExtension
	{
		public string ExtensionName => "test_v1_text_editor";
		public string Name => "Text Editor";
		public string Description => "Text Editor";
		public object Extension => new TextEditor();
		public void Initialize() { }
	}