Generalized Dockerfile to allow ARM builds

Dockerfile

@@ -15,12 +15,13 @@ WORKDIR /usr/src
 COPY . .
 
 # Build Rust binary
-RUN cargo build --target x86_64-unknown-linux-musl --release
+ENV CARGO_TARGET_DIR=/usr/src/target
+RUN cargo build --release
 
 # Remove debug symboles
-RUN strip /usr/src/target/x86_64-unknown-linux-musl/release/dmarc-report-viewer
+RUN strip /usr/src/target/release/dmarc-report-viewer
 
 # Build final minimal image with only the binary
 FROM scratch
-COPY --from=builder /usr/src/target/x86_64-unknown-linux-musl/release/dmarc-report-viewer /
+COPY --from=builder /usr/src/target/release/dmarc-report-viewer /
 CMD ["./dmarc-report-viewer"]

README.md

@@ -44,7 +44,7 @@ The latest version is automatically published as Docker image in the GitHub cont
 You can download the image using the command `sudo docker pull ghcr.io/cry-inc/dmarc-report-viewer`.
 
 ### Available Docker Tags
-The followng tags are available aside from the versioned tag for all individual releases:
+The following tags are available (aside from the versioned tag for all individual releases):
 * `latest` (Latest stable release)
 * `develop` (Last build from master branch)
 
@@ -104,7 +104,11 @@ You should also persist the certificate caching directory on your host file syst
 5. Use the help argument to list all possible configuration parameters: `dmarc-report-viewer --help`
 
 ### Docker Builds (Linux only)
-Use the command `docker build . --pull --tag dmarc-report-viewer` to build the tiny Docker image.
+The Dockerfile works for X86-64 and AArch64 (Raspberry Pi & Apple Silicon) architectures.
+1. Install Docker
+2. Check out this repository (or download and extract the ZIP file)
+3. Run the command `sudo docker build . --pull --tag dmarc-report-viewer` in the folder with this README file
+4. You should now be able to see the new Docker image using the command `sudo docker images`
 
 ## Acknowledgments
 - https://github.com/bbustin/dmarc_aggregate_parser was used as foundation for the slightly modified DMARC report parser