add a short readme

README.md

@@ -0,0 +1,13 @@
+# uuid-generator
+
+A short command line tool to generate and a UUIDv4 and print it to the screen.
+In its current form, relies on pledge() so will probably only compile on OpenBSD.
+
+To compile and run:
+
+```
+$ cc -o uuid-generator uuid-generator.c
+$ ./uuid-generator
+...
+```
+