Adds solution 2 file

2. useState/solution2.js

@@ -0,0 +1,54 @@
+import React from "react";
+import ReactDOM from "react-dom";
+
+import "./styles.css";
+
+// Random ID generator
+function generateId () {
+  return "_" + Math.random().toString(36).substr(2,9)
+}
+
+function Todo () {
+  const [todos, setTodos] = React.useState([])
+  const [input, setInput] = React.useState("")
+
+  const saveInput = (e) => setInput(e.target.value)
+
+  const addItem = () => {
+    setTodos( (todos) => todos.concat({
+      text: input,
+      id: generateId()
+    }))
+
+    setInput("")
+  }
+
+  const removeItem = (id) => {
+    setTodos( (todos) => todos.filter( (item) => item.id !== id ))
+  }
+
+  return (
+    <div>
+      <input 
+        type="text"
+        value={input}
+        placeHolder="New Todo"
+        onChange={saveInput}
+      />
+      <p>Input is: {input}</p>
+      <button onClick={addItem}>Add to list</button>
+
+      <ul>
+        {todos.map(({text, id}) => (
+          <li key={id}>
+            <span>{text}</span>
+            <button onClick={() => removeItem(id)}>Delete</button>
+          </li>
+        ))}
+      </ul>
+    </div>
+  );
+}
+
+const rootElement = document.getElementById("root");
+ReactDOM.render(<Todo />, rootElement);