New achievements

I suggest adding more achievements. The points one from this wonderful post: https://feedback.worldofpotter.eu/communities/1/topics/541-new-point-achievements

And in addition to that:

- Log in 500 days in a row

- Log in 750 days in a row

- Log in 1000 days in a row

- 15000 owls sent

- 20000 owls sent

- 500 riddles solved

- 750 riddles solved

- 500 anagrams solved

- 750 anagrams solved

- 750 topics created

- 1000 topics created

- 1500 topics created

- 200 assignments submitted

- 300 assignments submitted

I don't actually know how many assignments can be submitted total, but if possible, 400 or 500

- 1500 homeworks graded

- 2000 homeworks graded

- 2750 homeworks graded

- 4000 homeworks graded

- 5000 homeworks graded

- 750 topics answered

- 1000 topics answered

Adding these would remove the 'empty spaces' on the achievements page if I wrote it down correctly.