Update workaround for "Outside the Scope of Strong Parameters" 

The previous example of how to permit a hash of unknown keys used .tap, but had the side effect of logging an "Unpermitted parameters" message despite being a successful workaround. The proposed workaround is ever so slightly better, imo, because it won't result in an "Unpermitted parameters" message being logged.
Fix undefined method error for NilClass

Add .try to prevent undefined method error for NilClass.
Merge pull request #12609 from corwinkelly/patch-1

Update workaround for "Outside the Scope of Strong Parameters"