Ran `yarn dev` in keyserver and:
1. Confirmed migration 7 ran by checking the logs for the following:
```
[NODEM] (node:90015) DB version: 6
[NODEM] (node:90015) migration 7 succeeded.
```
2. Confirmed that the MySQL tables looks as expected by inspecting with the `mysql` CLI utility
Tested the above for three distinct scenarios:
1. Somebody has a broken setup due to the issues introduced in the previous diff (ran broken migration 6)
2. Somebody has never run any migration 6 and still has the columns
3. Somebody has never run any migration 6 and DOESN'T have these columns
To test all of these scenarios, I ran the following queries to undo the migration:
```
ALTER TABLE users ADD COLUMN public_key char(116) DEFAULT NULL, MODIFY hash char(60) COLLATE utf8mb4_bin NOT NULL;
ALTER TABLE sessions ADD COLUMN public_key char(116) DEFAULT NULL;
UPDATE metadata SET data = 5 WHERE name = "db_version";
```