Update README.md

README.md

@@ -15,8 +15,32 @@ ensure
 calaboose.new :socket => '/path/to/socket'
 ```
 
-As you can see the code above for Calaboose, ```ensure``` ensures that the code is always evaluated. That's why it's called ensure. So, it is equivalent to Java's and C#'s ```finally```. It's for high security, and ensuring the code is read before executed, ensure is kind of obscure, but one of the charms in Ruby.
+As you can see the code above for Calaboose, ```ensure``` ensures that the code is always evaluated. That's why it's called ensure. So, it is equivalent to Java's and C#'s ```finally```. It's for high security, and ensuring the code is read before executed, ensure is kind of obscure, but one of the charms in Ruby. An equivalent of ```ensure``` in C# just for reference, would be something like this:
+
+```c#
+try
+{
+   some_code();
+}
+catch(Exeption)
+{
+   handle_expeption();
+}
+finally
+{
+   this_code_is_always_executed();
+}
+```
+
+#### The Docker Image
+
+If the image is built ahead of time (by a rake task or bootstrap script), you can pass the name of the image to use when instantiating a Hoosegow/Calaboose instance.
+
+```ruby
+ENV['CALABOOSE_IMAGE']
+```
 
 Calaboose is not fully complete, and won't be until March 2017. As of now I'm keeping the source open for the people.
 
-Built for <a href="http://www.getprowl.com">Prowl</a>. Written by <a href="www.montanamendy.com">Montana Mendy</a>.
+Built for <a href="http://www.getprowl.com">Prowl</a>. Written by <a href="http://www.montanamendy.com">Montana Mendy</a>.
+