Picture phenotype RSS feed is broken

[philippbayer]

See https://opensnp.org/picture_phenotypes/3/feed

Actual error:

ActionView::MissingTemplate: Missing template picture_phenotypes/rss, application/rss with {:locale=>[:en], :formats=>[:html], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :slim]}.

I don't feel good when there's not at least 20 issues open