add list command, fix set command

app/generic.go

@@ -0,0 +1,10 @@
+package app
+
+// look if a key in a map exists, generic variant
+func Exists[K comparable, V any](m map[K]V, v K) bool {
+	if _, ok := m[v]; ok {
+		return true
+	}
+
+	return false
+}