Fix documented ruby code blocks formatting

README.md

@@ -162,6 +162,7 @@ Templates
 
   In `templates/freebsd/jail.conf.erb`:
 
+```ruby
 exec.start = "/bin/sh /etc/rc";
 exec.stop = "/bin/sh /etc/rc.shutdown";
 exec.clean;
@@ -190,6 +191,7 @@ Templates
   conf = template 'freebsd/jail.conf', if: INTERFACE, jails: JAILS
   file_write_once '/etc/jail.conf', conf
 end
+```
 
 
 Macros
@@ -225,6 +227,7 @@ Sample recipe
   Based on the previous template example (FreeBSD jails.conf
 template):
 
+```ruby
 require 'producer/stdlib'
 
 JAILS_ROOT  = '/var/jails'.freeze
@@ -318,6 +321,7 @@ template):
   conf = template 'freebsd/jail.conf', if: INTERFACE, jails: JAILS
   file_write_once '/etc/jail.conf', conf
 end
+```
 
 
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