Basically, I have this same question: https://www.odoo.com/es_ES/forum/help-1/question/openerp-7-web-non-root-url-prefix-33279. I see it has remain unanswered for more than a year. Sorry, I don't know if there's a way to bump it.

Anyway the question is: how to run Odoo with a url prefix? Let's say my domain is example.com. I want to have a proxy that passes /erp/ to localhost:8069, so that people going to example.com/erp/ get served the odoo site. The problem is that urls in the pages generated by odoo would be all wrong, for example /web instead of /erp/web.