Playground can't load assets when using APIRouter

[anhi]

Hi,

in a modularized application with APIRouter-instances that set their own prefix, loading the playground does not work, as the prefix path is not prepended for the assets.

This seems like a simple fix: replacing line 1032 of server.py with

f"{namespace}/playground" if isinstance(app, FastAPI) else f"{app.prefix}{namespace}/playground",

works for me. I've prepared a corresponding pull request.

[eyurtsev]

Thanks for the PR -- I'm taking a look -- will commandeer to add tests

[eyurtsev]

Had to open a new PR to push changes. Closing this PR in favor of: #236

[eyurtsev]

Fixed in #236