Add Activity Collection

Author: Gerrit Garbereder

Task-Tracker-Entities-Impl/src/commonMain/kotlin/com/garbereder/tasktracker/entities/ActivityCollectionImpl.kt

@@ -0,0 +1,18 @@
+package com.garbereder.tasktracker.entities
+
+class ActivityCollectionImpl : ActivityCollection {
+
+    private val list = mutableListOf<Activity>()
+    override fun add(activity: Activity) {
+        list.add(activity)
+    }
+
+    override fun iterator(): Iterator<Activity> = list.iterator()
+
+    override fun remove(activity: Activity) {
+        if (!list.contains(activity))
+            throw ActivityNotFoundException(activity)
+        list.remove(activity)
+    }
+
+}