show how flags work in nu (#145)

engine-q/nu_101/flag.nu

@@ -0,0 +1,29 @@
+
+### So in this case you have to pass in a parameter
+### Any parameter you type will work
+### If you don't type a parameter you get an error
+###
+### The syntax for this is
+### noflag hola
+###
+
+def noflag [x] {
+  echo $x
+}
+
+### The syntax for this is
+### flag -f
+### flag --flag
+
+### If you type anything else it does not work
+### For example
+### flag -flag
+### flag -f=hola
+### flag -f hola
+### flag -f = hola
+
+def flag [
+  --flag(-f)
+] {
+  echo $flag
+}