undefined method `foreign_keys'

I receive the following error after updating Schema Plus due to a deprecation warning:

```
.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/valuable-0.9.9/lib/valuable.rb:93:in `method_missing': undefined method `foreign_keys' for #<SchemaPlus::ForeignKeys::Config:0x007fa63ebd2068> (NoMethodError)
```
