db modifications from pr #778 need documentation

[nachog00]

One more addition I think we should add is updating the database CHANGELOG and the migration notes in migrations.rs with the change to write block (in the v1.0.0->1.1.0 migration).

Originally posted by @idky137 in #778 (comment)

[nachog00]

The original PR #778 already made it onto it's target due to PR merging miss-timings. Leaving this here to not loose track of it.

It's not clear to me what this means, should changes in 778 have introduced a migration? is that 1.0.0->1.1.0 migration the one introduced at #828 ?

[idky137]

Added context:

In an attempt to make the database more understandable we have started documenting all changes that take place in this code (along with improving documentation for the code that is already written).

Database changes are chunked into version bumps (internally referred to as database migrations), that follow the same update cycle as the zaino crates / bins, and are recorded in 2 places:

• database migrations implementation module:

https://github.com/zingolabs/zaino/blob/dev/zaino-state%2Fsrc%2Fchain_index%2Ffinalised_state%2Fmigrations.rs#L69

https://github.com/zingolabs/zaino/blob/dev/zaino-state%2Fsrc%2Fchain_index%2Ffinalised_state%2Fmigrations.rs#L528

• and the database change log:

https://github.com/zingolabs/zaino/blob/dev/zaino-state%2Fsrc%2Fchain_index%2Ffinalised_state%2FCHANGELOG.md

There is a v1.0.0->1.1.0 migration currently on Dev which we can add to until we put out our next release. There is currently one pr open which fixes some inconsistencies in the database serde and adds the changes in this migration (#828). It would be good for us to add the updated behaviour in dbv1::write_block to this migration's documentation also.

If possible I think it would be good for us to get these last few changes in so the dB is in good health for our first proper release.