Making the prelude-erc module more modular

1. Introduces the `my-fav-irc` list for custom autojoining
   your favorite channels
2. Introduces the `bye-erc-message` variable for customizing
   the Last Quit Message
3. Adds documentation so that users can take advantage of these features

modules/doc/README.md

@@ -11,7 +11,7 @@ following links.
 -   Common-Lisp
 -   CSS
 -   Emacs-Lisp
--   ERC
+-   [ERC](prelude-erc.md)
 -   Erlang
 -   Elixir
 -   Haskell

modules/doc/prelude-erc.md

@@ -0,0 +1,31 @@
+# Prelude ERC Quickstart
+
+## Customizing Server list
+
+If you want to join a list of servers on `M-x start-irc`, other than the default list, please redefine the variable `my-fav-irc` as follows in your personal config
+
+``` emacs-lisp
+(setq my-fav-irc '( "irc.freenode.net"
+                    "irc.oftc.net"
+                    "irc.mozilla.org"
+                    "irc.gnome.org"))
+```
+
+## Customizing Last Quit Message
+
+If you want to customize your IRC Last Quit Message from *Asta la vista* to something more funkier, please redefine `bye-irc-message` as follows
+
+``` emacs-lisp
+(setq bye-erc-message "adios")
+```
+
+## Reading NickServ passwords from auth-source plugin
+
+If you want to automatically authenticate while logging into IRC servers set the `erc-prompt-for-password` to nil as follows
+
+``` emacs-lisp
+(setq erc-prompt-for-password nil)
+```
+
+Now you can set password in plaintext in .authinfo file in the netRC format or you it encrypted in .authinfo.gpg file after setting up gpg in emacs
+