Review

There's something a little "off" with your routes. You have your root route defined as welcome#index, but that doesn't do anything. There is a "home" link there though that takes the user to /dogs/:id where :id is the id of the "current dog." If your notion of the home page of your site is a page about the currently logged in dog, that's what welcome#index should display, with some fallback to blank (or instructions) if there's no-one logged in or no current dog. 

You don't want to confound the user's expectation that url "/" would be in some sense the landing page, or home or root of the site. Your home button takes them somewhere else, which is strange.