Add datapackage and setup validation workflow

.github/workflows/validation.yml

@@ -0,0 +1,24 @@
+name: validation
+
+on:
+  pull_request:
+    branches:
+      - main
+  schedule:
+   schedule: # run automatically on main branch each Tuesday at 11am
+    - cron: "0 16 * * 2"
+
+
+jobs:
+
+  # Validate
+
+  validate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v3
+      - name: Validate data
+        uses: frictionlessdata/repository@v2
+        with:
+          packages: "datapackage.json"

README.md

@@ -1,5 +1,7 @@
 # PGP Metadata
 
+[![validation](https://github.com/princetongenizalab/pgp-metadata/actions/workflows/validation.yml/badge.svg)](https://github.com/princetongenizalab/pgp-metadata/actions/workflows/validation.yml)
+
 This repository is used to version and publish data from the [Princeton Geniza Project](https://geniza.princeton.edu/) (PGP). The data files are automatically exported and synchronized from the PGP database. Commits include co-author information where possible, to credit the researchers who are working on the data.
 
 Files in the data directory should _NOT_ be edited or modified directly.