use patches for chapter alignment updates

app/components/BookBuilder/Chapter/AlignmentBox.jsx

@@ -14,8 +14,14 @@ class AlignmentBox extends React.Component {
 
     if (!includes(['left', 'right'], position)) return
 
-    chapter.alignment[position] = !chapter.alignment[position]
-    update(chapter)
+    const patch = {
+      alignment: chapter.alignment,
+      id: chapter.id
+    }
+
+    patch.alignment[position] = !chapter.alignment[position]
+
+    update(patch)
   }
 
   render () {