use HashMap insted of ArrayList to store the timetables

src/main/kotlin/org/mosad/thecitadelofricks/hsoparser/CourseListParser.kt

@@ -36,17 +36,15 @@ class CourseListParser {
      * @param courseListURL the url to the course list page
      * @return a ArrayList<Course> with all courses or null if the request was not successful
      */
-    fun getCourseLinks(courseListURL: String): ArrayList<Course>? {
-        val courseLinkList = ArrayList<Course>()
+    fun getCourseLinks(courseListURL: String): HashMap<String, Course>? {
+        val courseLinkList = HashMap<String, Course>()
         try {
             val courseHTML = Jsoup.connect(courseListURL).get()
 
             courseHTML.select("ul.index-group").select("li.Class").select("a[href]").forEachIndexed { _, element ->
-                courseLinkList.add(
-                    Course(
-                        element.text(),
-                        element.attr("href").replace("http", "https")
-                    )
+                courseLinkList[element.text()] = Course(
+                    element.text(),
+                    element.attr("href").replace("http", "https")
                 )
             }
         } catch (ex: SocketTimeoutException) {