Use a more permissive speedup ratio on the CI
Disconnect from database in the application process

We did this before but reverted in
9cf9aea5b441882dc7b4edcfb06af4cd86cae68a.

I've revisited this and managed to solve the problem that caused the
revert.
Rake tasks only connect to db if they depend on :environment

See issue #125. This isn't a complete solution but it's a step.