Defined two functions.

list/list.h

@@ -1,15 +1,15 @@
 typedef struct Node{
-	unsigned long int id;
+	unsigned long int id;//what's this?
 	void *value;
-	struct Node *next;
-	struct Node *front;
-} Node;
+	Node *next;
+	Node *last;
+};
 
 typedef struct List{
 	Node *head;
 	Node *tail;
 	unsigned long int length;
-} List;
+};
 
 List *init_list();
 Node *init_node();
@@ -22,3 +22,18 @@ int popFromTail(List *p_list);
 unsigned long int len(List *p_list);
 Node *findById(List *p_list, unsigned long int id);
 Node *findByValue(List *p_list, char type[], void *value);
+
+
+int insertInHead(List *p_list, Node *p_node){
+	p_list->head->last = p_node;
+	//p_node->last = NULL;
+	p_node->next = p_list->head;
+	p_list->head = p_node;
+}
+
+int insertInTail(List *p_list, Node *p_node){
+	p_list->tail->next = p_node;
+	//p_node->next = NULL;
+	p_node->last = p_list->tail;
+	p_list->tail = p_node;
+}