Allow parameter filters to match multi-parameter attributes

[jpignata]

We're using the DateHelper in our application so in some places our permit list includes things like:

def book_params
  params[:book].permit( 
    :"published_at(1i)",                                                      
    :"published_at(2i)",                                                      
    :"published_at(3i)",                                                      
    :"published_at(4i)",                                                      
    :"published_at(5i)",
   ...
  )
end

This change matches multi-parameter attributes based upon the head of the key so you can just include :published_at in the above example.

[zlw]

Why not just use regexp for this?

keys.select do |key|
  key.match /#{filter}\(\d+i\)/
end

[jpignata]

#index was the fastest way to figure it out when I measured different approaches. I agree it's cleaner with a Regexp though.

[zlw]

i found regexp are almost always faster than anything when it comes to strings. maybe with other regexp it will be faster:

key.match /\A#{filter}\(\d{1}i\)\z/i

[dhh]

I'd rather we just default to permit :published_at will also just automatically allow :published_at(x) -- instead of all this extra configuration. If you want to take a stab at a pull request that does that, please open a new ticket. I posted the same message to pull request #21.