Add docs

README.md

@@ -1,3 +1,53 @@
-![Build Status](https://github.com/Surnet/get-json-matrix/actions/workflows/test.yml/badge.svg)](https://github.com/Surnet/get-json-matrix)
+[![Build Status](https://github.com/Surnet/get-json-matrix/actions/workflows/test.yml/badge.svg)](https://github.com/Surnet/get-json-matrix)
 
 # Surnet/get-json-matrix
+
+This action gets a GitHub Action Matrix from a JSON.
+
+## Inputs
+
+### `filepath`
+
+The path to the JSON file (defaults to: ./matrix.json)
+
+## Example usage
+
+This runs for the file ./matrix.json in our repository and outputs the 
+
+```yaml
+name: Run for every X in JSON
+
+on:
+  push:
+
+jobs:
+  get-matrix:
+    name: Get Matrix from JSON
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    outputs:
+      matrix: ${{ steps.matrix.outputs.matrix }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Get Matrix
+        id: matrix
+        uses: Surnet/get-json-matrix@v1
+        with:
+          filepath: ./matrix.json
+
+  run-for-everything:
+    name: Run for each Key Value combination in the JSON
+    needs: get-matrix
+    permissions: {}
+    runs-on: ubuntu-latest
+    strategy:
+      matrix: ${{ fromJson(needs.get-matrix.outputs.matrix) }}
+    steps:
+      - name: Echo matrix
+        run: |
+          echo "${{ matrix.key }}"
+          echo "${{ matrix.value }}"
+```