Improve migration performance

[lekhasy]

Currently, migration took about 20-30 seconds which is too slow for testing.
We also need to reset db after each test so 20-30 seconds wait time between each tests is not viable.
We need a solution for this, so we can bring it down to sub 1 second.

[henrinormak]

Any background on why migrations are so slow? I have not got further than migrations, so I'm inclined to ask whether this means regular queries are also equally as slow?