Add model and add event listeners

src/nodes/StringNode.ts

@@ -1,11 +1,17 @@
 import { AbstractNode, NodeMods } from './AbstractNode'
+import { Path } from '../model/Path'
+import { DataModel } from '../model/DataModel'
 
 export class StringNode extends AbstractNode<string> {
   constructor(mods?: NodeMods<string>) {
     super(mods)
   }
 
-  render(field: string, value: string) {
-    return `<span>${field}</span> <span>${value || ''}</span>`
+  updateModel(el: Element, path: Path, model: DataModel) {
+  }
+
+  render(path: Path, value: string, model: DataModel) {
+    return this.wrap(path, model, 
+      `<span>${path.last()}</span> <input value="${value || ''}"></input>`)
   }
 }