column_name, not columnname

[Max Kanat-Alexander]

	I think that we discussed this in IRC perhaps a few times, and maybe on
some bug somewhere, but generally it's a lot easier to read database
column names if they're named like "column_name" instead of like
"columnname."

	New columns should be named like "column_name." I just noticed that we
added a column to the attachments table named "isurl."

	-Max