feature: cargo shuttle init

[christos-h]

Introduce an init function to cargo-shuttle that will initialise the barebones of a project (similar to cargo init). cargo shuttle init <name>

This should probably:

1. Add an Init(ProjectName) variant to Command in args.rs
2. Call cargo init --lib via the cargo crate
3. Automatically add the crate-type = ["cdylib"] to cargo.toml
4. Add the shuttle-service deps top cargo.toml.

Bonus points - have a separate cargo init command for each framework supported. For example with Rocket:

1. cargo shuttle init-rocket <name>
2. As above, but also add the feature flags: shuttle-service = { version = "0.2", features = ["web-rocket"] }
3. Also create hello-world scaffolding

#[macro_use]
extern crate rocket;

use rocket::{Build, Rocket};

#[get("/")]
fn index() -> &'static str {
    "Hello, world!"
}

#[shuttle_service::main]
async fn rocket() -> Result<Rocket<Build>, shuttle_service::Error> {
    Ok(rocket::build().mount("/hello", routes![index]))
}

[nahuakang]

I'd be happy to claim this if no one else is working on it yet and it's not high priority time-wise on shuttle's roadmap :)

Edit: After asking around and doing some investigation, it seems that cargo init writes naively to files and we could use toml-edit for modifying an existing Cargo.toml file.

[brokad]

I'd be happy to claim this if no one else is working on it yet and it's not high priority time-wise on shuttle's roadmap :)

Thanks @nahuakang!

Edit: After asking around and doing some investigation, it seems that cargo init writes naively to files and we could use toml-edit for modifying an existing Cargo.toml file.

Sounds like a plan!

[nahuakang]

First PR is merged. I'll start working on the bonus points (might be off for a few days but will definitely continue on the issue) :)