Add interface shown in video

Facade/BadLogger.cs

@@ -1,4 +1,4 @@
-public class BadLogger
+public class BadLogger : IBadLogger
 {
     public void Log(string message, LogType logType, LogTarget target, Exception? ex)
     {

Facade/IBadLogger.cs

@@ -0,0 +1,4 @@
+public interface IBadLogger
+{
+    void Log(string message, LogType logType, LogTarget target, Exception? ex);
+}

Facade/Logger.cs

@@ -1,6 +1,6 @@
 public class Logger : ILogger
 {
-    private readonly BadLogger _logger;
+    private readonly IBadLogger _logger;
     public Logger()
     {
         _logger = new BadLogger();

README.md

@@ -11,4 +11,8 @@ I came up with the following 5 Design Patterns:
 2. [Decorator Pattern](Decorator)
 3. [Observer Pattern](Observer)
 4. [Singleton Pattern](Singleton)
-5. [Facade Pattern](Facade)
+5. [Facade Pattern](Facade)
+
+To run them just `cd` into each folder and run `dotnet run`.
+
+Note: You will need the .Net Core SDK installed to run these.