Linked List

This is practice to learn about linked list

What i created:

1. LinkedList class to represent the full list
2. ListNode class to create a node

and the following methods:

• append(value) adds a new node containing value to the end of the list
• prepend(value) adds a new node containing value to the start of the list
• size returns the total number of nodes in the list
• getFirst returns the head in the list
• getTail returns the tail node in the list
• at(index) return node at given index
• pop() removes last element from list
• contains(value) return true if value exist in the list