Add IntelliJ Idea template for gitignore

IntelliJIdea.gitignore

@@ -0,0 +1,21 @@
+# IntelliJ IDEA
+.idea/
+*.iml
+*.ipr
+*.iws
+
+# Gradle
+.gradle/
+build/
+
+# Maven
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+
+# Other
+.DS_Store