Consider this scenario:
I had an app that was using Rails version 4.0.0.
My goal was to upgrade it to Rails 4.1.9. To do so, I tried to upgrade it step by step: first, upgrading to 4.0.13, then 4.1 and finally 4.1.9.
Everything went smoothly. All the tests were passing using RSpec.
Finally, I tried to run my server with rails s
. Booom! Ruby crashed.
Then, I used bin/rails s
. Everything went ok.
So I think if you have different version of rails set up in your system, it's safer to use bin/rails
option.
P.S. To make sure that my assumption is correct, I removed all rails version except 4.1.9 and then I tried to rerun the server with rails s
. No crash this time.
Hope this clarifies.