Add non-invasive nix shell integration

[sisyphushappy]

Hi @chshersh,

I watched your FunctionalFest presentation about cake-slayer, and I think this is a great project for the Haskell community. The choices you made really seem to address a lot of the reservations I've felt about investing in Haskell for a production application. I am still a Haskell beginner so I'm hoping that by grokking this template project, I can level myself up to proficiency.

Anyway, this change is based on a Tweag blog post, which explains how to integrate Nix with stack in a non-invasive manner.

I tested the change on my NixOS machine by building...

stack build

running the server...

stack run piece-of-cake-slayer

and running the test commands from the readme...

$ curl localhost:8080/items

$ curl -XPOST \
    -H 'Content-Type: application/json' \
    localhost:8080/createItem \
    -d '{"tag": "Item", "text": "New item"}'

$ curl -XPOST \
    -H 'Content-Type: application/json' \
    localhost:8080/deleteItem \
    -d '1'

Finally, I ran the unit tests...

$ stack test
piece-of-cake-slayer> test (suite: piece-of-cake-slayer-test)
                                  

Unit tests
  Database tests
    Item
      Gets all items
      Creates new item
      Deletes item

Finished in 0.0185 seconds
3 examples, 0 failures

piece-of-cake-slayer> Test suite piece-of-cake-slayer-test passed
Completed 9 action(s).

[chshersh]

Hi @sisyphushappy, thanks for the kind words about my talk! 😊
However, I'm not maintaining this project anymore.

[sisyphushappy]

No problem, thanks anyway 🙂!