Add a readme with basic instructions.

Change-Id: I00501ac713f88f36146e9681c8ac44f26b8f94bf
Add a readme section about tests.

Change-Id: Iba82f7dc40961cae33120a6a1a03c5f981dab291
Merge branch 'add-readme'
Add info to the readme about the DB reset before the tests.

Also establish a convention to create items on the fly if they're
going to be modified in the tests.

Change-Id: Ia2dd041b287c0bb10eb1f53d699d8f1b582f05e0