feat: add stacks

Author: benben6515

interview/neetcode/implement/array:dynamic-array.js renamed to interview/neetcode/implement/1-array:dynamic-arrays.js

@@ -0,0 +1,17 @@
+class Stack {
+  constructor() {
+    this.stack = new Array()
+  }
+
+  push(n) {
+    this.stack.push(n)
+  }
+
+  pop() {
+    return this.stack.pop()
+  }
+
+  size() {
+    return this.stack.length
+  }
+}