integrations/pgp: Mention GnuPG integration.

integrations/pgp.md documents usage of the unstable internal PGP
implementation.  It is important to note to users that it is possible
(and generally the right thing to do for production use) to use an
external implementation, usually GnuPG.

Signed-off-by: Andrew Yu <andrew@andrewyu.org>

1 files changed, 15 insertions, 4 deletions

diff --git a/integrations/pgp.md b/integrations/pgp.md
index a5804a06..2e826ef0 100644
--- a/integrations/pgp.md
+++ b/integrations/pgp.md
@@ -4,16 +4,27 @@ title: "aerc-wiki: Integrations/PGP"
 
 # PGP
 
-> At the moment PGP Support is still in it's early stages and will likely
-> change as time goes on. Tickets relating to this can be found in
+To use GnuPG, simply set the following in `aerc.conf`.  Unless if you want to
+tinker with the internal implementation, **it is highly recommended that you
+use gpg or similar external implementations.**
+```conf
+[general]
+pgp-provider=gpg
+```
+
+When the above configuration option is unset or set to `internal`,
+aerc uses an internal OpenPGP implementation.
+
+> At the moment internal PGP support is still in it's early stages and will
+> likely change as time goes on. Tickets relating to this can be found in
 > ~sircmpwn's tracker: [#353](https://todo.sr.ht/~sircmpwn/aerc2/353)
 > [#354](https://todo.sr.ht/~sircmpwn/aerc2/354)
 > [#355](https://todo.sr.ht/~sircmpwn/aerc2/355)
 > [#357](https://todo.sr.ht/~sircmpwn/aerc2/357)
 > [and more](https://todo.sr.ht/~sircmpwn/aerc2?search=label%3A%22pgp%22)
 
-**Please be aware:** at the moment PGP support requires you to export your
-private keys. Please ensure that your home directory is protected against
+**Please be aware:** at the moment internal PGP support requires you to export
+your private keys. Please ensure that your home directory is protected against
 unauthorised access.
 
 To create a PGP-Keyring and fill it with your keys from GPG, you can run the