SchemaPlus/schema_plus — pull request #191 by lowjoel (2014-12-23 20:46:15+00:00)
Title: Duplicate the given options from the migration instead of modifying in place

This allows the same options to be used by different parts of the migration script, e.g.

```ruby
hash = { references: :users }
t.references :creator foreign_key: hash
t.references :updater foreign_key: hash
```

Which would be invalid otherwise.