how to add another competition

years of competitions occur in these places:
```
grep -r Y2017 src/

src/Presenter/Registration.hs:  Y2017 -> Form_2017.tc
src/Presenter/Model/Competition.hs:data Year = Y2014 | Y2015 | Y2016 | Y2017 | E
src/Presenter/History.hs:  Y2017 -> Just termcomp2017
```


