Strategies for optimising in production

[Adil]

When developing locally, I do not minify assets (my javascript and css files are usually formatted so they're easy to read and navigate). However, when I push my code to production this is an obvious stumbling block. My question is the following: how would I go about keeping my source code minified in production, but decompressed in development?

My initial idea was to use a git hook which would call a minifier and minify my assets. However, as I'm using AppEngine, I'm not in a position to do such a thing.
Any ideas?