Update README.md

README.md

-# DataStructures
+# Data structures
+
+Fork this repository and submit your code via pull request.
+
+##Linked List
+
+
+### Requirements
+
+Implement a singly linked list:
+
+- You may not use the `LinkedList` or `ArrayList` class or any other predefined Java collections
+- Your linked list must have a node inner class to represent each element
+- Your linked list must have add, remove, contains, find, size, get, copy and sort methods
+- Method definitions:
+	- add -- add an element to the list
+	- remove -- remove an element (specified by numeric index) from the list
+	- contains -- returns true if the element is in the list, false otherwise
+	- find -- returns the element's index if it is in the list, -1 otherwise
+	- size -- returns the current size of the list
+	- get -- returns the element at the specified index
+	- copy -- returns a new linked list containing the same values (look up deep versus shallow copy)
+	- sort -- sorts the list using your algorithm of choice. You must perform the sorting yourself (no fair using someone else's library)
+
+
+### Optional features
+
+- implement your linked list as a generic class that can store any type of object
+- Add a reverse method
+- Add a slice method that returns a copy of a subset of the element of the list (eg slice(2,8) returns a new linked list containing elements #2,3,4,5,6,7 -- but not 8)