Allow a blacklist listing filters

[tracedwax]

We want to preserve active generation of filters, while
opting out of certain filters, for example associations.

Sometimes associations can be prohibitively large, for
example when there are 100,000 users and several models
which belong_to :user. That filter would have too many
items for the list to display correctly, and was causing
serious performance issues.

Example:

class User < ActiveRecord::Base
  has_many :posts
end

class Post < ActiveRecord::Base
  belongs_to :user 
end

ActiveAdmin.register Post do
  unfilter :user
end

[travisbot]

This pull request passes (merged 7b54309f into 1a20a16).

[jpmckinney]

I don't know about the name unfilter. I know you're trying to mirror the method filter. Maybe we can just call it remove_filter? (I would also rename delete_filter to remove_filter).

[stefanpenner]

I think the naming is fine, unless consensus around some other name is reached, we should just leave it.
#preventbikeshedding

[jpmckinney]

It's not bikeshedding. unfilter doesn't make sense - it's not even a word. remove_filter is clearer. And to follow the conventions and style of the rest of the code, new methods should be called remove_* not delete_*.

[alexandru-calinoiu]

I totally agree with @jpmckinney remove_filter sounds like a very reasonable name, unfilter is not a word (I know, who cares about what I think but I will really like this feature implemented)

[stefanpenner]

looks like consensus has been reached, awesome. remove_filter it is. @tracedwax got a chance to update the pr?

[tracedwax]

Done - changed the naming to remove_filter as discussed.

[travisbot]

This pull request passes (merged d4908c0 into a8cc231).

[jpmckinney]

Merged, thanks!