Add documentation for docker builds (#128)

Build/CompilingInDocker.md

@@ -0,0 +1,83 @@
+## Docker builds
+
+Docker builds are managed from the `Makefile` in the root folder. Typing `make` will print out some helpful information.
+
+### Prerequisites
+
+Required:
+
+- `docker`
+- `docker-compose`
+- `Makefile`
+
+Recommende:
+
+- `vs code`
+
+### Build Image
+
+`iSEG` can be build entirely using a docker build image based on ubuntu 18.04. The build image is published on [Dockerhub](https://hub.docker.com/repository/docker/itisfoundation/iseg-ubuntu-buildkit).
+The build image contains all required 3rd party dependencies and compilers to build `iSEG`.
+If required, the build image can be rebuild using the `Dockerfile` in the `docker` subfolder.
+
+To create a new one:
+
+```
+make create-build-image
+```
+
+To publish it to the `Dockerhub`:
+
+```
+make publish-build-image.
+```
+
+Make sure to increase the version for every new build image.
+
+### Compiling
+
+Compilation is done by mounting the source folder into the build container and executing a build script. Compiled binaries are kept in a docker-volume to avoid recompilation after every build invocation.
+
+To compile in release:
+
+```
+make build-release
+```
+
+To compile in debug:
+
+```
+make build-debug
+```
+
+To clean the build folders (i.e. removing the build volume)
+
+```
+make clean-build
+```
+
+### Debugging
+
+Visual Studio Codes remote container debugging can be used as follows:
+
+```
+make debug-in-container
+```
+
+This creates a `devcontainer` settings and starts a new vs code instance using the build-image. By default, the `iSeg` debug target is active. New ones can be added by editing a `launch.json` file.
+
+### Run
+
+`iSeg` can be started via
+
+```
+make run-release
+```
+
+or
+
+```
+make run-debug
+```
+
+as well as from the debug container. This is achieved by mounting the `X11` socket and the `DISPLAY` variable into the build containers.

README.md

@@ -40,3 +40,4 @@ For installing EIGEN just download and extract the [source code](http://eigen.tu
 - Windows/Visual Studio [instructions](Build/CompilingWindows.md)
 - MacOS/Clang++ [instructions](Build/CompilingMacOS.md)
 - Ubuntu [github action](.github/workflows/build.yml)
+- With Docker images [instructions](Build/CompilingInDocker.md)