Queue & Stack implemented with linked list

- fix gitignore file

.gitignore

@@ -1,6 +1,6 @@
 
-# Created by https://www.gitignore.io/api/linux,kotlin,intellij+all
-# Edit at https://www.gitignore.io/?templates=linux,kotlin,intellij+all
+# Created by https://www.gitignore.io/api/linux,kotlin,gradle,intellij+all
+# Edit at https://www.gitignore.io/?templates=linux,kotlin,gradle,intellij+all
 
 ### Intellij+all ###
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio and WebStorm
@@ -101,7 +101,6 @@ modules.xml
 
 # Package Files #
 *.jar
-!gradle/**/*.jar
 *.war
 *.nar
 *.ear
@@ -127,4 +126,23 @@ hs_err_pid*
 # .nfs files are created when an open file is removed but is still being accessed
 .nfs*
 
-# End of https://www.gitignore.io/api/linux,kotlin,intellij+all
+### Gradle ###
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# # Work around https://youtrack.jetbrains.com/issue/IDEA-116898
+# gradle/wrapper/gradle-wrapper.properties
+
+### Gradle Patch ###
+**/build/
+
+# End of https://www.gitignore.io/api/linux,kotlin,gradle,intellij+all

.gradle/buildOutputCleanup/cache.properties

@@ -1,2 +0,0 @@
-#Sun Mar 10 15:15:32 CET 2019
-gradle.version=4.10

build/kotlin/compileKotlin/caches-jvm/lookups/counters.tab

@@ -1,2 +0,0 @@
-4
-0