Update README.md with TODOs

Author: cszach

README.md

@@ -1,2 +1,29 @@
-# java-data-structures
-:gear: Implementation of common data structures in Java
+Java data structures
+====================
+
+> Honorable mention to professor Eustrat Zhupa in the University of
+> Rochester Computer Science Department.
+
+Lists
+-----
+
+- [x] Singly linked list
+- [ ] Doubly linked list
+- [ ] Queue
+- [ ] Stack
+
+Trees
+-----
+
+- [ ] Tree
+- [ ] Binary tree
+- [ ] Binary search tree (BST)
+- [ ] Heap
+
+Sorting
+-------
+
+- [ ] Insertion sort
+- [ ] Selection sort
+- [ ] Merge sort
+- [ ] Quick sort