"rspec-rails" is already declared in the "test" section of the Gemfile.
This was generating this Bundler warning:
Your Gemfile lists the gem rspec-rails (>= 0) more than once.
You should probably keep only one of them.
Remove any duplicate entries and specify the gem only once.
While it's not a problem now, it could cause errors if you change the
version of one of them later.