[guide] Buildbot

Buildbot queues

We have four main PyOP2 Buildbot queues: pyop2-master and pyop2-testing.

pyop2-master builds the master branch nightly and on every merge.
pyop2-testing is built on every push to any branch but master and gh-pages. Can also be scheduled manually: enter the name of your branch in "Branch to build", and press "Force Build".
pyop2-tox builds with different Python interpreters using tox on every push to any branch. Can also be scheduled manually: enter the name of your branch in "Branch to build", and press "Force Build".
pyop2-vagrant builds in a VM using vagrant on every push to any branch. Can also be scheduled manually: enter the name of your branch in "Branch to build", and press "Force Build".

We have two main Firedrake Buildbot queues: firedrake-master and firedrake-testing.

firedrake-master builds the master branch nightly and on every merge.
firedrake-testing is built on every push to any branch but master and gh-pages. Can also be scheduled manually: enter the name of your branch in "Branch to build", and press "Force Build".

There are further queues for nightly builds of the FEniCS components we depend on:

ffc builds the master branch of the MAPDES FFC fork nightly and on every merge.
ffc-testing builds any branch but master of the MAPDES FFC fork on every push.
fiat builds the master branch of the MAPDES FIAT fork nightly and on every merge.
fiat-testing builds any branch but master of the MAPDES FIAT fork on every push.
ufl builds the master branch of the MAPDES UFL fork nightly and on every merge.
ufl-testing builds any branch but master of the MAPDES UFL fork on every push. The side effect is that we detect whenever a change in one of these dependencies breaks our master branch.

The master builders should ALWAYS BE GREEN - TESTS SHOULD ALWAYS PASS.
If a master builder is not green, the person who made the change that turned it from green to red should fix it.
Pull requests should only be merged if the revision of the branch to be merged has passed