Add docs

src/cert.h

@@ -3,6 +3,20 @@
 
 #include "basic.h"
 
+// This is an utility to create self-signed certificates
+// useful when testing HTTPS servers locally. This is only
+// meant to be used by people starting out with a library
+// and simplifying the zero to one phase.
+//
+// The C, O, and CN are respectively country name, organization name,
+// and common name of the certificate. For instance:
+//
+//   C="IT"
+//   O="My Organization"
+//   CN="my_website.com"
+//
+// The output is a certificate file in PEM format and a private
+// key file with the key used to sign the certificate.
 int http_create_test_certificate(HTTP_String C, HTTP_String O, HTTP_String CN,
     HTTP_String cert_file, HTTP_String key_file);