Array values in the parameter to `Gem.paths=` are deprecated.

gistfile1.txt

Array values in the parameter to `Gem.paths=` are deprecated.
Please use a String or nil.
An Array (...) was passed in from bin/rails:3:in `load'

Solution
========
https://github.com/rubygems/rubygems/issues/1551

If you came to this issue by googling the error specified in the description of this issue, you should know that it has already been fixed in spring-1.6.4 and all you need to do is to update to latest spring and regenerate binstubs, like this:

$ bundle update spring && bundle exec spring binstub --remove --all && bundle exec spring binstub --all

If you see 
==========

There is a version mismatch between the spring client (1.7.2) and the server (1.6.4).
Restarting to resolve.


$ spring stop

Will solve it!