* Added "Migrate" to the title because these steps can also be used to migrate the instance to another server
* Added an optional step to reinstall pleroma (esp. for migrating servers)
* Currently the steps threw an error 'could not execute query: ERROR: function "activity_visibility already exists with the same argument types'
* I added a new step to drop and recreate an empty pleroma-database
* I played around with the `-c` and `-C` options of pg_restore, but dropping and recreating seemd to be the only way I got it working
* This was tested on Debian Stretch, psql (PostgreSQL) 9.6.15
Large part of it was no longer true (i.e none of the changes need
recompilation anymore and you can't brick an instance by changing them,
it's not necessary to manually truncate the db manually anymore)
Ilja