added local build incl. curl

restic/Dockerfile

@@ -0,0 +1,3 @@
+FROM restic/restic
+# Adding curl to talk with the Prometheus Gateway
+RUN apk add --update curl

restic/docker-compose.yml

@@ -2,6 +2,7 @@ version: '2'
 services:
   restic:
     image: restic/restic
+    build: .
     container_name: restic
     hostname: restic
     restart: on-failure:3