Add Example to README

README.md

@@ -3,3 +3,24 @@
 Single header library for cli apps
 
 Used in ctrff and npi-build
+
+## Example
+
+```cpp
+#include <cli-fancy.hpp>
+
+void ShowString(const cf7::command::ArgumentList& data) {
+  std::cout << "Input String was: " << cf7::command::GetArg(data, "i") << std::endl;
+}
+
+int main(int argc, char* argv[]) {
+  cf7::arg_mgr mgr(argc, argv);
+  mgr.SetAppInfo("test", "1.0.0");
+  mgr.AddCommand(
+      cf7::command("show", "Show an input String")
+          .AddSubEntry(cf7::command::sub("i", "input", "Input String", true))
+          .SetFunction(ShowString));
+  mgr.Execute();
+  return 0;
+}
+```