Added Readme for Plugin

GameLib.Plugin/GameLib.Plugin.RiotGames/README.md

@@ -0,0 +1,45 @@
+![GameLib.NET](Resources/GameLibPluginLogo128px.png "GameLib.NET Riot Games")
+Riot Games Plugin for GameLib.NET
+======
+
+[Riot Games](https://www.riotgames.com/en) plugin for ![GameLib.NET](../../Resources/GameLibNET-Logo-16px.png "GameLib.NET") [GameLib.NET](README.md).
+
+The plugin will deliver information about the installation status of the `Riot Games` launcher as well the installed games within the launcher.
+
+## Installing
+
+The plugin is already bundled with the core library ![GameLib.NET](../../Resources/GameLibNET-Logo-16px.png "GameLib.NET") [GameLib.NET](README.md)
+
+## Additional information the plugin is providing
+
+To get the additonal information this plugin is providing just cast `IGame` to `GogGame`.
+
+
+```CSharp
+using GameLib;
+using GameLib.Plugin.Gog;
+using GameLib.Plugin.Gog.Model;
+
+var launcherManager = new LauncherManager();
+
+// not required to cast here just to add to the documentation
+var launcher = (GogLauncher?)launcherManager.GetLaunchers()
+    .Where(launcher => launcher.Name == "Riot Games")
+    // Plugin ID could also be used instead of the name
+    //.Where(launcher => launcher.Id == new Guid("938071a9-925e-4b1d-ae17-61a05ef5ec28"))
+    .FirstOrDefault();
+
+if (launcher is not null)
+{
+    var games = (IEnumerable<GogGame>)launcher.Games;
+    foreach (var game in games)
+    {
+
+        Console.WriteLine($"Game ID: {game.GameId}");
+        foreach (var item in game.GetType().GetProperties().Where(p => p.Name != "GameId"))
+        {
+            Console.WriteLine($"\t{item.Name}: {item.GetValue(game)}");
+        }
+    }
+}
+```