spm

Mention that tpm is POSIX shell compatible

diff --git a/README.pod b/README.pod
@@ -11,7 +11,8 @@ B<tpm> I<COMMAND> I<ENTRY>
 tpm is a tiny shell script which is heavily inspired and largely
 compatible with pass(1). Just like pass it uses gpg2(1) to securely
 store your passwords, the major difference between pass and tpm is that
-the latter is a lot more minimal.
+the latter is a lot more minimal. Furthermore, tpm is written entirely
+in POSIX shell.
 
 Invoking tpm consists of specifying a command either I<insert> or
 I<show> and supplying one entry as a target. If I<insert> is specified