added keystore to gitignore
added keystore to gitignore

chwnFlyPig/Crouton,neofoniemobile/Crouton,zhaochuanTeam/Crouton,yummy222/Crouton,bellycard/Crouton,wangwangheng/Crouton,remind101/Crouton,xu33liang33/Crouton,kidfolk/Crouton,kzganesan/Crouton,simple88/Crouton,hgl888/Crouton,Appstrakt/Crouton,pengleelove/Crouton,hongnguyenpro/Crouton,coreform/Crouton,jferlisi/Crouton,Brooks0129/Crouton,hejunbinlan/Crouton,zllbird/Crouton,loulousky/Crouton,beamly/Crouton,mikepenz/Crouton,keyboardsurfer/Crouton,java02014/Crouton