Add links to usage instructions to README

Author: manuelmeurer

README.md

@@ -29,7 +29,11 @@ At least the CSS files for the navbar are required, and the JS files for dropdow
 
 ## Usage
 
-The gem [bootstrap_navbar](https://github.com/krautcomputing/bootstrap_navbar) is used to generate the HTML. Please refer to the [README](https://github.com/krautcomputing/bootstrap_navbar#usage) of that gem for detailed instructions on how to generate the navbar.
+The gem [bootstrap-navbar](https://github.com/krautcomputing/bootstrap-navbar) is used to generate the HTML. Please refer to the gem's [README](https://github.com/krautcomputing/bootstrap_navbar#usage) and the following Wiki entries for detailed instructions on how to generate the navbar:
+
+[Usage with Bootstrap 2.x](https://github.com/krautcomputing/bootstrap-navbar/wiki/Usage-with-Bootstrap-2.x)
+
+[Usage with Bootstrap 3.x](https://github.com/krautcomputing/bootstrap-navbar/wiki/Usage-with-Bootstrap-3.x)
 
 ## Contributing