gregbell/active_admin — pull request #1928 by Daxter (2013-02-17 07:01:12+00:00)
Title: [1093] HABTM Select Filters

For #1093

Besides fixing dropdowns for HABTM, these changes make it so `id` isn't necessary in your filter. Assuming Foo HABTM Bars, the below now works as you'd expect:
```ruby
ActiveAdmin.register Foo do
filter :bars
end
```

#### TODO
+ get multiselect working
+ force Formtastic to get rid of the mysterious hidden input that it's
adding