+ Use the correct data type to evaluate the error codes when
opening the SQLite database.

+ Add a way to migrate the database schema on iOS
+ This partly reverts the changes to the db location

+ Add a column to the table `task`
+ Add the value to the record when modeling tasks

… via cellular data

+ iOS handles this on a session basis and not on a per task basis, so we have
to configure two different sessions. One that allows downloading via cellular
data and one that doesn't.