Update README.md with contribution information

Julien LepillerThu Apr 18 14:25:39+0200 2019

54b501d

nani/app/furiganatextview/src
namelast commitdate
androidTest/Add furiganaMon Apr 15 20:09:48+0200 2019
main/Add furiganaMon Apr 15 20:09:48+0200 2019
test/Add furiganaMon Apr 15 20:09:48+0200 2019