Add OpenAPI checker

Signed-off-by: jld3103 <jld3103yt@gmail.com>

build/openapi-checker.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+
+for path in core/openapi.json apps/*/openapi.json; do
+	composer exec generate-spec "$(dirname "$path")" "$path" || exit 1
+done
+
+files="$(git diff --name-only)"
+changed=false
+for file in $files; do
+    if [[ $file == *"openapi.json" ]]; then
+        changed=true
+        break
+    fi
+done
+
+if [ $changed = true ]
+then
+	git diff
+    echo "The OpenAPI specifications are not up to date"
+    echo "Please run: bash build/openapi-checker.sh"
+    echo "And commit the result"
+    exit 1
+else
+    echo "OpenAPI specifications up to date. Carry on"
+    exit 0
+fi