add script to register let's encrypt keys and other useful bin/postal commands

script/register_lets_encrypt.rb

@@ -0,0 +1,15 @@
+require_relative '../config/application'
+require 'postal/lets_encrypt'
+
+if ARGV[0].nil?
+  puts "e-mail address missing"
+  exit 1
+end
+
+begin
+  Postal::LetsEncrypt.register_private_key(ARGV[0])
+  puts "Done"
+rescue => e
+  puts "#{e.class}: #{e.message}"
+  exit 1
+end