Add better description of what a normalized graph cache is

[jnak]

In the design exploration, it is not clear how the normalize graph is different than the regular flat map.

The examples look exactly the same:

• flat map:

  {
  ROOT: {
  posts: [
    { __ref: 1 },
    { __ref: 2 },
  ],
  },
  1: {
  id: 1,
  title: 'GraphQL Rocks!',
  author: { __ref: 3 },
  },
  2: {
  id: 2,
  title: 'GraphQL Rocks!',
  author: { __ref: 3 },
  },
  3: {
  id: 3,
  name: 'Gouda',
  },
  }

• normalized graph:

  {
  ROOT: {
  posts: [
    {…}, // Reference to <1>
    {…}, // Reference to <2>
  ],
  },
  1: {
  id: 1,
  title: "GraphQL Rocks!",
  author: {…} // Reference to <3>
  },
  2: {
  id: 2,
  title: "Caching Is Hard",
  author: {…} // Reference to <3>
  },
  3: {
  id: 3,
  name: 'Gouda',
  },
  }

Would you mind updating the description of the normalized graph cache?

[nevir]

Yeah, let me try explaining here to see where I'm missing info:

The main difference is that in the second example, ROOT.posts[0] maps to the exact same javascript object as 1. Whereas in the first example, that mapping is represented by an intermediate object (the { __ref: 1 }). Does that clarify?