Add "saved-by" parameter for instagram

[ashtw]

Instagram adds a "saved-by" parameter to links presented on the user "saved posts" page, so that when such a URL is shared it provides strong connections in the invisible social graph. For example:

https://www.instagram.com/p/xxxxxxxxxxx/?saved-by=user

Please consider stripping the "saved-by" parameter. Thanks.

[newhouse]

@ashtw ahh yes, I see it. It seems like it would be safe to remove such a parameter, but this starts to increase the number of parameters that I'm blocking that are "domain-specific", and I'm starting to think that I need to have a more robust solution for those scenarios. I may add it shortly anyways and create a better solution somewhere down the line...stay tuned.