Add project files.

MyOffice.Core/Extensions/BoolExtensions.cs

@@ -0,0 +1,14 @@
+namespace MyOffice.Core.Extensions;
+
+public static class BoolExtensions
+{
+	public static string ToLowerCase(this bool value)
+	{
+		return value.ToString().ToLower();
+	}
+
+	public static string? ToLowerCase(this bool? value)
+	{
+		return value == null ? null : value.ToString()?.ToLower();
+	}
+}