message: Update write-to-dynamodb.md
diff: @@ -15,7 +15,8 @@ The details of Single Table Design can be a bit of work to learn but `create-sst
  In ElectroDB each concept in your data model is called an `Entity` and you can specify right in your application code. Let's start by creating a new Entity for comments in `services/core/article.ts`
  ```js
  -const CommentEntity = new Entity({
  +const CommentEntity = new Entity(
  + {
  model: {
  version: "1",
  entity: "Comment",
  @@ -51,16 +52,18 @@ const CommentEntity = new Entity({
  byArticle: {
  index: "gsi1",
  pk: {
  - field: "pk",
  + field: "gsi1pk",
  composite: ["articleID"]
  },
  sk: {
  - field: "sk",
  + field: "gsi1sk",
  composite: ["commentID"],
  }
  }
  },
  -})
  + },
  + Dynamo.Configuration
  +)
  ```
  This defines a new `CommentEntity` with the fields `articleID`, `commentID`, and `text`. `articleID` and `commentID` are marked `required` and `readOnly` (which means it cannot be changed after creation).
  