Karlis,
take a look at
Ruby on Rails. It is a useful framework for creating web-applications, written in
Ruby, an object-oriented scripting language.
In fact you would need to create two syntax highlighters: one for Ruby files (.rb) and one for embedded Ruby (.rhtml). The latter is plain html with marked up Ruby code in it.
Simple project management with syntax highlighting for both data types would already be more than enough (for me at least).