Added superlikes to heat score

[Seluj78]

Closes #243

[Seluj78]

@supalarry can you take a look at the heat score function and tell me if you want to change something to how the score is calculated ?

[supalarry]

All good, except using constants would be recommended in cases like

score += likes_received * 2

The 2 can be defined as constant. That should give autocompletion and when writing tests you just use constants. If you had unit test and you were to change this 2 to 3 in code, then your unit test also would need to be updated manually.

[supalarry]

Looks good to me now! I think the constants now tell more about what the multipliers are in the first place.