- #append adds a new node to the end of the list
- #prepend adds a new node to the start of the list
- #size returns the total number of nodes in the list
- #head returns the first node in the list
- #tail returns the last node in the list
- #at(index) returns the node at the given index
- #pop removes the last element from the list
- #contains? returns true if the passed in value is in the list and otherwise returns false.
- #find(data) returns the index of the node containing data, or nil if not found.
- #to_s represent your LinkedList objects as strings, so you can print them out and preview them in the console. The format should be: ( data ) -> ( data ) -> ( data ) -> nil
- #insert_at(index) that inserts the data at the given index
- #remove_at(index) that removes the node at the given index.