Dockerfile: use docker to build Linux compat bin

I use NixOS, so this is for release

Signed-off-by: Dylan Turner <dylan.turner@tutanota.com>

Dockerfile

@@ -0,0 +1,10 @@
+# Set up Debian as a build system
+
+FROM debian:latest
+RUN apt-get update && apt-get install -y \
+    build-essential
+
+# Set up environment to build for Debian
+WORKDIR /proj
+ENTRYPOINT [ "make -j$(nproc)" ]
+

README.md

@@ -75,3 +75,10 @@ From a folder with an `acbs.ini` file, run the following commands:
 
 You can optionally specify the folder containing an acbs.ini by providing it as a second argument.
 
+## Build
+
+Use docker. We have a Dockerfile in the main directory which will build an x86\_64 Linux compatible binary via Debian
+
+Build Image: `docker build -t acbs-bldr .`
+Run Image: `docker run --rm -v .:/proj -e HOST_UID=$(id -u) -e HOST_GID=$(id -g) acbs-bldr`
+