Add relationship between "template story" and "client instance story"

还没有人认领这个 Issue。

**Before we start...:**

- [x] I checked the documentation and didn't find this feature
- [x] I checked to make sure that this feature has not already been requested

**Branch/Commit:**

main branch

**Describe the feature:**

Please include a detailed description of the feature you are requesting and any detail on it’s expected behavior.

> **As a user**
> **I clone a template story**
> **And then I add it to my client project**
> **And I see a relationship between the template story and the client instance story**

**Problem:**

Please include a detailed description of the problem this feature would solve.

> **As an admin**
> **I want to be able to keep a relationship between a template story and a client instance story**
> **So that I can later get insights from past upgrade projects**

**Resources:**

Let's say that there is a story (https://points.ombulabs.com/projects/181/stories/3334) in a template for a version jump (4.2 to 5.0) and I go ahead and clone that story for a new client project.

Then I would expect to see a relationship in the database that connects the template story to the instance story.

In the future, one would get insights from other client projects.

A person who is working on estimate an instance of https://points.ombulabs.com/projects/181/stories/3334 could talk to client project Acme's team and ask them about their experience with it.

**I will abide by the [code of conduct](https://github.com/fastruby/points/blob/main/CODE_OF_CONDUCT.md)**

首先追踪 story 克隆流程，以及 template story 和 client instance story 的模型或数据库关系。完成的标准是，克隆操作会持久化两个 story 之间可查询的链接，从而支持所请求的未来 project insights；issue 中未指定任何文件或测试。

由索引模型根据 Issue 内容生成。