During development, it is fairly common to cycle between writing
code and testing that code. Generally the testing happens within
the test suite, but frequently it is more convenient to test things
by hand when tracking down a bug, or when doing some exploratory
coding. In many situations, however, this becomes inconvenient -
for instance, in a REPL, or in a stateful web application, restarting
from the beginning after every code change can get pretty tedious.
This module allows you to reload your application classes on the
fly, so that the code/test cycle becomes a lot easier.