added docker

README.md

@@ -59,6 +59,64 @@ python jira_jotty_sync.py --direction=jotty-to-jira
 python jira_jotty_sync.py --direction=both
 ```
 
+## Docker (Raspberry Pi 5 / ARM64)
+
+### Build for ARM64
+
+On Raspberry Pi 5 (native ARM64):
+
+```bash
+docker build -t jotty-jira-sync:arm64 .
+```
+
+From another machine using buildx:
+
+```bash
+docker buildx build \
+   --platform linux/arm64 \
+   -t jotty-jira-sync:arm64 \
+   .
+```
+
+### Prepare runtime config files
+
+Create local config files in the project folder:
+
+```bash
+cp sync_config.json.template sync_config.json
+# Optional if you prefer env-based auth instead of putting secrets in JSON
+touch .env
+```
+
+### Run container
+
+The container runs `python jira_jotty_sync.py --direction both` by default.
+
+```bash
+docker run --rm \
+   --name jotty-jira-sync \
+   -v "$(pwd)/sync_config.json:/app/sync_config.json:ro" \
+   -v "$(pwd)/.env:/app/.env:ro" \
+   -v "$(pwd)/sync_mapping.json:/app/sync_mapping.json" \
+   jotty-jira-sync:arm64
+```
+
+Run a one-way sync instead:
+
+```bash
+docker run --rm \
+   -v "$(pwd)/sync_config.json:/app/sync_config.json:ro" \
+   -v "$(pwd)/.env:/app/.env:ro" \
+   -v "$(pwd)/sync_mapping.json:/app/sync_mapping.json" \
+   jotty-jira-sync:arm64 --direction jira-to-jotty
+```
+
+Notes:
+
+- Keep `.env` and `sync_config.json` private because they contain credentials.
+- `sync_mapping.json` is mounted so state persists across container runs.
+- If you do not use `.env`, remove that `-v` mount and rely on `sync_config.json`.
+
 ### CLI overrides
 
 Override config values from the command line: