Document the Nix and Docker usage

Author: ibbem

INSTALL.md

@@ -30,11 +30,14 @@ The following hints apply for most Linux users:
 > It is best to install required software (e.g., Docker, Maven) using your distro's package manager if it is available.
 
 ### Setup
-Simply build the image using the provided script:
+Clone and navigate to this repository.
+Then, simply build the image using the provided script:
 ```shell
-./docker.sh build 
+./docker.sh build
 ```
 
+This will automatically build the Docker container using Nix if Nix is installed on your system.
+
 ### Execution
 Once the image has been build, you can start the demo with
 ```shell
@@ -43,6 +46,37 @@ Once the image has been build, you can start the demo with
 
 ## Nix Setup
 
+Nix can be used to reproducibly build both, a standalone derivation and a docker container.
+Nix aids in reproducible builds whereas Docker aids in reproducible execution.
+
+To use Nix, you need to have [Nix](https://nixos.org/download/) installed on your system.
+See [REQUIREMENTS.md](REQUIREMENTS.md) for instructions on how to install Nix and optionally also Docker.
+
+### Standalone Build
+
+If you have flake's enabled, you can just use
+```shell
+nix run https://github.com/VariantSync/DiffDetective-Demo.git#.
+```
+
+Otherwise, clone and navigate to this repository.
+Then simply build and run the Demo using
+```shell
+nix-build
+./result/bin/DiffDetective-Demo
+```
+
+### Using a Docker Image
+
+If you have Nix installed, the `docker.sh` script will automatically build this demo using Nix.
+Hence, the instructions are the same as for docker:
+Clone and navigate to this repository and execute the following:
+```shell
+./docker.sh build
+./docker.sh demo
+```
+
+
 ## Expected Output
 
 The expected output is close to the output shown at the end of the [screencast](https://www.youtube.com/watch?v=q6ight5EDQY).

REQUIREMENTS.md

@@ -8,7 +8,7 @@ None
 
 We do not require a certain operating system or prepared environment.
 For downloading this demo, we recommend Git (installing Git is explained in [this article](https://github.com/git-guides/install-git)).
-The setup is tested on Windows 10, WSL2, Manjaro, Ubuntu, and MacOS Monterey.
+The setup is tested on Windows 10, WSL2, Manjaro, Ubuntu, NixOS and MacOS Monterey.
 
 ### Toolchain
 This demo is a Maven project based on Java 17. Thus, it requires a [Java development toolkit](https://www.oracle.com/java/technologies/downloads/) of version 17 or higher, and [Maven](https://maven.apache.org/). 
@@ -22,14 +22,18 @@ Installing DiffDetective follows the default maven workflow and is explained on
 ## Virtualization: Docker or Nix
 For easy replication, this demo also comes with a Nix package and a Docker container, which can be used on any system supporting Nix or Docker, respectively.
 The Nix and Docker setup will take care of all requirements and dependencies (including DiffDetective) and will build the demo to a single runnable JAR file.
-_Note_: Nix and Docker are neither required by the demo nor DiffDetective! They only serve to ease the setup for you. You may use either Nix or Docker but you do not need both.
+_Note_: Nix and Docker are neither required by the demo nor DiffDetective! They only serve to ease the setup for you.
+
+### Docker
 
 How to install Docker depends on your operating system:
 
 - _Windows or Mac_: You can find download and installation instructions [here](https://www.docker.com/get-started).
 - _Linux Distributions_: How to install Docker on your system, depends on your distribution. The chances are high that Docker is part of your distributions package database.
   Docker's [documentation](https://docs.docker.com/engine/install/) contains instructions for common distributions.
 
+### Nix
+
 How to install Nix, also depends on your operating system.
 Head to the [NixOS website](https://nixos.org/download/) and follow the installation instructions for your system.
 Follow the download instructions for `Nix: the package manager`, not `NixOS: the Linux distribution`!