Add Rendering ERB as a ruby til.

ruby/rendering-erb.md

@@ -0,0 +1,32 @@
+# Rendering ERB
+
+If you have a string that contains ERB templating, you can quickly generate
+the resulting string with the following code snippet:
+
+```ruby
+require 'erb'
+
+some_template_string = <<-TEXT
+The top
+<% 5.times  do |i| %>
+Item <%= i + 1 %>
+<% end  %>
+The bottom
+TEXT
+
+puts ERB.new(some_template_string).result
+```
+
+This will print the following to stdout:
+
+```
+The top
+Item 1
+Item 2
+Item 3
+Item 4
+Item 5
+The bottom
+```
+
+[source](http://www.stuartellis.eu/articles/erb/)