Upgrading from 3.0 to 3.1 I receive a `Sass::SyntaxError at /` `() isn't a valid CSS value.`

[Lordnibbler]

I am experiencing an error after upgrading bootstrap-sass from 3.0 to 3.1 on a Rails 4.0.2 project.

I have @import 'bootstrap' in my application.css.scss file. When I try to use a mixin, like @include scale(0); I see Sass::SyntaxError at / () isn't a valid CSS value

Full backtrace: https://gist.github.com/Lordnibbler/f6e6a4a4a24b41357af3

I have reproduced this issue in a brand new Rails app, you can find it here for reference: https://github.com/Lordnibbler/bootstrap-sass-3.1-bug

To reproduce:

• clone my repo
• bundle
• rails s
• load localhost:3000

[glebm]

This should be OK now on master:

gem 'bootstrap-sass', git: 'https://github.com/twbs/bootstrap-sass'

[glebm]

Fix released in v3.1.0.1

[Lordnibbler]

@glebm like a boss, thanks for the quick support 😺