Allow configuring deployment branches in environments

[marcoieni]

#2127 added support for declaring environments.
We now want to allow people to declare the deployment branches of their environments.

TOML:

[[environments]]
name = "production"

[[environments.branches]]
name = "main"

I used the syntax [[environments.branches]] because there could be more branches per environment. Let me know if I'm missing something or you have a better syntax in mind.

UI screenshot:

[amustaque97]

My suggestion would be to follow the format

[environments.development]
branch = ["dev_db"]
tag = ["v1.0-dev"]

[environments.production]
branch = ["prod_db"]
tag = ["v1.0"]

This TOML structure is better because it is:

1. Simpler to read and maintain
2. More predictable for the code that loads it
3. Expandable without breaking changes
4. Cleaner than arrays of tables
5. Accurate for real-world use (one config per environment)

Please feel free to add if I'm missing anything 🙂

[Kobzol]

Yeah we need a way to associate the branches to the environment. So either

[environments.foo]
branches = []

or

[[environments]]
name = "foo"
branches = []

the first would allow us to remove the validation for unique environment names.

[marcoieni]

My idea was wrong. You are both right! I like the style of the second proposal from Jakub since it's simpler 👍

We don't need tags at the moment I think

[Kobzol]

since it's simpler

[environments.foo] should be a bit easier to both implement and consume, because you implicitly get the environments as a map where the keys have to be unique, rather than just a list of environments, so we wouldn't have to validate that there aren't two environments with the same name.

But it doesn't really matter much, both will do the job.

[marcoieni]

Both works for me! I'm not sure which style we adopt for the rest of the config files