Update README.md

Author: KtorZ

README.md

@@ -7,4 +7,48 @@ every six hours, which is then pushed to a cache used in the [continuous integra
 
 ['Ogmios repository']: https://github.com/CardanoSolutions/ogmios
 [network synchronization workflow]: https://github.com/CardanoSolutions/ogmios/blob/master/.github/workflows/network-synchronization.yaml
-[continuous integration workflow]: https://github.com/CardanoSolutions/ogmios/blob/master/.github/workflows/continuous-integration.yaml
+[continuous integration workflow]: https://github.com/CardanoSolutions/ogmios/blob/master/.github/workflows/continuous-integration.yaml
+
+# Usage
+
+see [action.yml](https://github.com/CardanoSolutions/gh-action-cardano-node-ogmios-docker-sync/blob/master/action.yml) for all possible options.
+
+
+## Basic 
+
+Be aware that this will do a full resync on every run. 
+
+```yaml
+steps:
+- uses: actions/checkout@v2
+
+- uses: CardanoSolutions/cardano-node-ogmios-docker-sync@v1
+```
+
+## With cache and multiple networks
+
+```yaml
+strategy:
+  matrix:
+    network: [ testnet, mainnet ]
+
+steps:
+- uses: actions/checkout@v2
+
+- id: date
+  shell: bash
+  run: |
+      echo "::set-output name=value::$(/bin/date -u "+%Y%m%d")"
+
+- uses: actions/cache@v2
+  with:
+    path: ${{ runner.temp }}/db
+    key: cardano-node-${{ matrix.network }}-${{ steps.date.outputs.value }}
+    restore-keys: |
+      cardano-node-${{ matrix.network }}
+
+- uses: CardanoSolutions/cardano-node-ogmios-docker-sync@v1
+  with:
+    db-dir: ${{ runner.temp }}/db
+    network: ${{ matrix.network }}
+```