useful things while debugging a rails app you have not written yourself

debug-rails-app-written-by-other.txt

1. view paths ?
2. where are the layout and view file located ?
3. is the database.yml valid ? 
   sanity check: eyeball if it is running locally.
4. any "very" old libs and/or known security vulnerabilities ?

for (1) can delete a partial and see the stacktrace

something like 

```
Missing partial shared/foo with {:locale=>[:en], :formats=>[:html], :handlers=>[:erb, :builder, :jbuilder, :axlsx, :coffee, :haml, :csvbuilder, :liquid, :writeexcel]}. Searched in:
  * "../app/themes/new_default/views"
  * "../app/views"
  * "../app/themes/default/views"
  * "../gems/devise-2.2.4/app/views"
  * "../app/views"
  * "../app/themes/default/views"
  * "../devise-2.2.4/app/views"

```

for (2) check for logs for rendered layout
eg. `Rendered devise/sessions/new.html.haml within layouts/public (9.2ms)`
and search layout in view path as per (1)

for (3) can do a simple "rails console"