Rails 5

[Alphabetus]

Its a pitty that we cant use it on Rails 5 too.

[MyklClason]

Hmmm, just set this up on Rails 5? Here is how I went about it:

1. Add the gem per instructions
2. Copy the config from the website.
3. Add path to the master file within the config. I used /app/assets/images/favicons/master.png. The favicons were created in the /app/assets/images/favicon/ folder. Seems useful to keep the master out of that folder as it has lots of files in it, so left it as it was. Could have also left it in the images folder as "favicon_master.png but easy to end up with lots of images there too.
4. Increase the timeout from 30 seconds to 100 seconds via rails generate favicon -t 100 as per the instructions in the timeout error. Seems 30 seconds may not be enough to generate the favicons and run the generator. I could see that going up to 300 seconds in some cases.

The error said (at the end of the stack trace):
Operation timed out after 30 seconds, pass a -t option for a longer timeout (RuntimeError)