Sqlite3 application_id and user_version are now set to identify the
database is a builder-web database, and the user_version represents the
schema version.
The 'build' table is extended with a 'main_binary' column. This
represents the main binary artifact from the build. This is decided by
there being exactly one file in bin/.
A migration tool is written that does both migrations and rollbacks, and
migration and rollback is implemented for the above mentioned change.
Each time stamp has an ID that can be linked to. Currently, there's no
mechanism for getting the fragment. A solution could be to wrap the
timestamp in an anchor.
