adjust gitignore and add gradle wrapper

.gitignore

@@ -1,14 +1,11 @@
-.gradle
-build/
-!gradle/wrapper/gradle-wrapper.jar
+### Gradle/Java ###
+**/.gradle
+**/build/
 !**/src/main/**/build/
 !**/src/test/**/build/
 
 ### IntelliJ IDEA ###
-.idea/modules.xml
-.idea/jarRepositories.xml
-.idea/compiler.xml
-.idea/libraries/
+**/.idea
 *.iws
 *.iml
 *.ipr
@@ -42,4 +39,10 @@ bin/
 .vscode/
 
 ### Mac OS ###
-.DS_Store
+.DS_Store
+
+### Go ###
+go.sum
+
+### Build ###
+/hakureiUpdate.sh