added gradle build support, mainly to seamlessly integrate with intellij or eclipse
added gradle build support, mainly to seamlessly integrate with intellij or eclipse

yottamoto/java-koans,matyb/java-koans,DavidWhitlock/java-koans,matyb/java-koans,DavidWhitlock/java-koans,yottamoto/java-koans,yottamoto/java-koans,matyb/java-koans