Opening unrecognized file extensions for text files

[briarfox]

I've been playing around with bottle and would really like to be able to open other extensions besides txt. I've used the recommended bottle extension .tpl for bottle templates. I can not edit these in pythonista. I could have them as txt but I'd like to stay with the recommended naming convention. If I was working exclusively on my ipad, I'd just name them .txt but when importing from my desktop the tpl is a pain. I currently have to open them in textastic to edit them.