How to read the source code of a web site in Ruby on Rails?

I'm an experienced software engineer, but new to rails. I have just started a hobby project rigy.io , which based on Sharetribe.

I have gone through a trailing material and got a basic knowledge of rails. But when I went into SHaretribe's source code, still fills difficult to understand it.

What is the best way to read the source code of a web site in Ruby on Rails? Is there something like a debugger, when I click a button on the page, shows what happened in the background?