Add Discord server to README and Getting Started

README.asciidoc

@@ -17,3 +17,5 @@ http://erlang.mk/guide/getting_started.html[Get started]
 Tested and supported on
 http://erlang.mk/guide/installation.html#_on_unix[Linux, FreeBSD, OSX]
 and http://erlang.mk/guide/installation.html#_on_windows[Windows].
+
+Get help! https://discord.gg/x468ZsxG[Discord server].

doc/src/guide/getting_started.asciidoc

@@ -350,7 +350,8 @@ Bootstrap targets:
 
 This guide should provide any other answer. If not, please
 open a ticket on https://github.com/ninenines/erlang.mk/issues[the official repository]
-and we will work on improving the guide.
+and we will work on improving the guide. For any other questions,
+please visit the https://discord.gg/x468ZsxG[erlang-mk channel on Discord].
 
 Commercial support is available through Nine Nines. Please contact
 Loïc Hoguin by sending an email to mailto:[email protected][].