Run database migrations from distributed binary

[walkah]

Summary

Problem

Unless I'm mistaken, we currently need a clone of the repo / source to run the diesel migrations. It looks, though, like we're embedding the migrations in the binary - but I can't see any way to trigger them.

Impact

Need source to run migrations (can't just use the distributed binary).

Solution

I don't know enough about diesel, but it looks like automigrations are a possibility (should be the simplest, near term solution).

[matheus23]

We already run migrations inside the binary for test purposes (because they're stood up on-the-fly), here:

fission-server/fission-server/src/test_utils/ephermeral_db.rs

Lines 22 to 29 in 53ffd0c

	let mut conn = PgConnection::establish(&format!("{}/{}", base_url, db_name))
	.context("Cannot connect to postgres database.")?;
	conn.run_pending_migrations(MIGRATIONS)
	.map_err(|e| anyhow!(e))
	.context("Could not run migrations")?;

We need to make that code invokable from the binary CLI, too.

I'm pretty sure that actually embeds the migrations in the binary, given this:

fission-server/fission-server/src/db/mod.rs

Lines 9 to 12 in 53ffd0c

	use diesel_migrations::EmbeddedMigrations;
	/// The migrations available at compile-time
	pub const MIGRATIONS: EmbeddedMigrations = embed_migrations!("migrations/");

So I'm 90% sure that's an easy task.