add ERD for MVP after creating lists & list_items dwyl/mvp#356

.github/workflows/deploy.yml

@@ -18,7 +18,7 @@ jobs:
           toolchain: stable
       - run: (test -x $HOME/.cargo/bin/mdbook || cargo install --vers "^0.4" mdbook)
       - run: mdbook build && mdbook test # In case of custom book path: mdbook build path/to/mybook && mdbook test path/to/mybook
-      - uses: JamesIves/github-pages-deploy-action@4.1.7
+      - uses: JamesIves/github-pages-deploy-action@4.4.1
         with:
           branch: gh-pages # The branch the action should deploy to.
           folder: book # The folder the action should deploy.

src/mvp/15-lists.md

@@ -8,47 +8,61 @@ Let's fix that by introducing `lists`!
 
 ## Quick Recap
 
-Until this point we've _deliberately_ kept the `MVP`
-as lean as possible to avoid complexity.
+Up till this point we've _deliberately_ kept the `MVP`
+as lean as possible to avoid complexity. <br />
 The ERD is currently just:
 
 ![erd-before-lists](https://user-images.githubusercontent.com/194400/231414683-6fce1fd8-aead-471d-8789-a4a0111f7ce8.png)
 
 Just the handful of tables
 you've already seen in the previous sections.
 
-Our reasons for adding `lists` now are:
+Our reasons for adding `lists` _now_ are: <br />
 **a)** Separate `lists` 
 for different areas of life/work 
 is on our 
 [product roadmap](https://github.com/dwyl/product-roadmap). 
-specifically:
-[dwyl/app/**issues/271&&](https://github.com/dwyl/app/issues/271)
+_specifically_:
+[dwyl/app/**issues/271**](https://github.com/dwyl/app/issues/271)
 <br />
 **b)** We want to use `lists` 
 as the basis for organizing 
 and 
 [re-ordering `items`](https://github.com/dwyl/mvp/issues/145). <br />
-**c)** `lists` will unlock other functionalty we have planned
+**c)** `lists` will unlock other functionality we have planned
 that will make the `App` more _useful_.
 
 
 ## Create `Lists` Schema
 
-Create the `lists` and `list_items` database schemas
+Create the `lists` and `list_items` tables
 with the following 
 [**`mix phx.gen.schema`**](https://hexdocs.pm/phoenix/Mix.Tasks.Phx.Gen.Schema.html)
 commands:
 
 ```sh
-mix phx.gen.schema List lists person_id:integer status:integer text:string person_id:integer
-mix phx.gen.schema ListItems list_items item_id:references:items list_id:references:lists position:integer person_id:integer
+mix phx.gen.schema List lists person_id:integer status:integer text:string
+mix phx.gen.schema ListItems list_items item_id:references:items list_id:references:lists person_id:integer position:float
 ```
 
-
-At the end of this step,
+Once we run `mix ecto.migrate`,
 we have the following database
 [Entity Relationship Diagram](https://en.wikipedia.org/wiki/Entity%E2%80%93relationship_model)
 (ERD):
 
-![mvp-erd-list_items](here)
+![mvp-erd-list_items](https://user-images.githubusercontent.com/194400/232926700-6226ef42-774c-41b0-906e-6fbfe21efc6a.png)
+
+The `gen.schema` command only creates the migration files
+and the corresponding schema in the 
+[`lib/app`](https://github.com/dwyl/mvp/tree/main/lib/app) 
+directory of our `Phoenix App`.
+It does not create any `CRUD` functions or tests.
+This is fine because _most_ of what we need is bespoke.
+
+We _manually_ created the following files:
+
++ test/app/list_test.exs
++ test/app/list_items_test.exs
+
+> **TODO**: hyperlink these two files, once they are merged into `main`.
+