application.js so it won't be bundled with the rest of the project's scripts. I'll add a script tag for the library to just the pages that need it, which works locally in development mode. And then inevitably I deploy and the additional files can't be found on the server because they haven't been precompiled.
It is in the docs, but I always seem to forget that for Sprockets to precompile anything other than
application.js, the additional files must be specifed in
config.assets.precompile += ['another_file.js']
That's all there is to it.