Ignore large build folders in Docker builds

Leonidas-from-XIV · Leonidas-from-XIV · commit 054f27316496 · 2026-04-13T16:56:06.000+02:00
On my system `docker build` uploads about 2GB of data from Dune's
`_build` and OPAM's `_opam` folder which takes a long time and isn't
needed as the Docker image builds the code from scratch.

This PR includes it so it only takes a few seconds to start building the
container.
diff --git a/.dockerignore b/.dockerignore
@@ -1 +1,3 @@
 Dockerfile*
+/_opam/
+/_build/

Original file line number	Diff line number	Diff line change
`@@ -1 +1,3 @@`
`1`	`1`	`Dockerfile*`
	`2`	`+/_opam/`
	`3`	`+/_build/`