because we shouldn't always be building and running code
glorious is a process manages. glorious itself runs a unit.
A unit is the unit of functionality that glorious considers. Think of this as a service in supervisord terms. A unit in glorious, though, can have more than one slot. This is where the fun begins.
A slot is the literal set of commands that glorious will run.
Together, units add logic to determine which slot to run. This allows us dynamically change what slot we're running based on system conditions.
An example of where this is useful is if you need to develop code against a larger system, but don't want to run the development code yourself. At Mixmax, we often have docker containers that we pull down and run instead of running our gulp based dev process, so that we only need to run the necessary dev processes when essential.