Add Stack.

src/data-structures/stack/Stack.js

@@ -0,0 +1,28 @@
+import LinkedList from '../linked-list/LinkedList';
+
+export default class Stack {
+  constructor() {
+    this.linkedList = new LinkedList();
+  }
+
+  isEmpty() {
+    return !this.linkedList.tail;
+  }
+
+  peek() {
+    if (!this.linkedList.tail) {
+      return null;
+    }
+
+    return this.linkedList.tail.value;
+  }
+
+  push(value) {
+    this.linkedList.append({ value });
+  }
+
+  pop() {
+    const removedTail = this.linkedList.deleteTail();
+    return removedTail ? removedTail.value : null;
+  }
+}