Comparedb

[brutasse]

Sorry, it looks like I suck at branches... I started a new branch from brutasse:error-messages (previous pull request) instead of master. This request is for the last 3 commits, let me know if I should apply them to a fresh branch instead.

I've been playing with comparedb and I find this feature really nifty. I had 2 issues to get it to work:

• my local postgres install only accepts the 'postgres' user and won't create a UTF8 database if I don't pass it a specific template. I added an optional NASHVEGAS settings that lets the user specify his own commands with custom arguments. I've been hesitating between making this setting a command-line option but it's quite simple this way and falls back to simple createdb, dropdb and pg_dump calls if no setting is provided. (otherwise I'd have to map the management command's options with the postgres command, inevitably forgetting some use cases).
• Once I got comparedb working it wasn't outputting anything when I changed something in the models. Maybe I'm getting this wrong but I think comparedb should compare the current database with a fresh database created with syncdb. A switch to syncdb for the _compare-suffixed database properly shows missing indices, columns, tables and constraints.

Let me know what you think, Bruno

[paltman]

i have merged these and others in to master. Thanks!