Update README.md with contribution information

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

54b501d

nani/app/.idea
namelast commitdate
codeStyles/Initial commitSat Apr 06 13:19:46+0200 2019
gradle.xmlAdd furiganaMon Apr 15 20:09:48+0200 2019
misc.xmlAdd dictionary downloadSat Apr 06 18:57:04+0200 2019
runConfigurations.xmlInitial commitSat Apr 06 13:19:46+0200 2019
vcs.xmlInitial commitSat Apr 06 13:19:46+0200 2019