README: add GPG part

README-GPG.md

@@ -1,4 +1,4 @@
-# Using TREZOR as hardware GPG agent
+# Installation
 
 First, verify that you have GPG 2.1+ [installed](https://gist.github.com/vt0r/a2f8c0bcb1400131ff51):
 

README.md

@@ -1,4 +1,4 @@
-# Using TREZOR as a hardware SSH agent
+# Using TREZOR as a hardware SSH/GPG agent
 
 [![Build Status](https://travis-ci.org/romanz/trezor-agent.svg?branch=master)](https://travis-ci.org/romanz/trezor-agent)
 [![Python Versions](https://img.shields.io/pypi/pyversions/trezor_agent.svg)](https://pypi.python.org/pypi/trezor_agent/)
@@ -12,4 +12,7 @@ See SatoshiLabs' blog post about this feature:
 - https://medium.com/@satoshilabs/trezor-firmware-1-3-4-enables-ssh-login-86a622d7e609
 
 ## SSH usage
-See the following [link](README-SSH.md) for instructions.
+See the following [link](README-SSH.md) for instructions.
+
+## GPG usage
+See the following [link](README-GPG.md) for instructions.