change login avatar in my Rails app for non Facebook users and install friendly_id gem

Work to be done in detail: In a nutshell, exactly as the project name describes. 1. The default avatar given to a person who logs into my Ruby on Rails app is a question mark, '?' I want to change this to a different image file, which I will give to the programmer. 2. At present a user sees in the browser address bar, when they log in, something like, [login to view URL] I want to change the '24' to something else, so people can't see how many users I have.