Create /sales page, orders#sales controller action, and view/orders/sales.html.erb.
Add views/orders/purchases page.
Clean up nav bar links into 2 dropdowns.
Control user's ability to edit their own history.  Remove controller actions accordingly.  Then remove the corresponding views.
Homepage does not load in Heroku.  Attempt routing syntax update.
revert
Fix attempt. Think issue is at index.html.erb
Undo
Trying to get homepage to render on Heroku, damn it.
test nothing in listing/index.html.erb view.
that worked, now testing removal of only part of the loop (if anything works then it is not the controller).
returned everything in view, but commented out listing.user.name (attempting to display :name of the user *based on user_id*, however there may be OLD listings that do not have user associations.
That appeared to be it.  Earlier, I deleted all of the Users via the rails console (by doing User.delete_all).  However, I did NOT delete the Listings.  This left Listings that had no User, so when index was trying to render 'name' based on listing.user.name, I was getting an error, because it was trying to display the Listing with that listing's user's name, but that Listing no longer had a user (because I deleted it) so it was rendering an error when attempting to render listings#index aka listings/index.html.erb.