rails 3 built-in rake tasks, where are they located?

I can put my custom rake tasks in lib/tas开发者_Python百科ks/, but where are the built-in ones (i.e. db:migrate, db:seed, etc) stored?

I looked in: [INSTALLATION_DIRECTORY]/gems/rails-[VERSION]/lib/tasks but couldn't find that path. Maybe it matters that I'm using RVM?

I'd like to inspect their source for some inspiration.

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Have a look at /activerecord/lib/active_record/railties/databases.rake for the database related rake tasks. All the other rake tasks are also present in *.rake files, so you can run a find . -name "*.rake" in the gems directory to find others.