fix: switch to global env vars

.woodpecker.yml

@@ -2,7 +2,7 @@ pipeline:
   backend:
     image: rust
     environment:
-      - PG_DATABASE_URL=postgres://postgres:password@database:5432/postgres
+      - DATABASE_URL=postgres://postgres:password@database:5432/postgres
     commands:
       - curl -fsSL https://deb.nodesource.com/setup_16.x | bash - &&\
       - apt update && apt-get -y --no-install-recommends install nodejs
@@ -12,9 +12,9 @@ pipeline:
       - sed -i 's%url = "http:\/\/localhost:5000"%url = "http:\/\/librepages-conductor:5000"%' config/default.toml
       - make dev-env
       - make build
-      - DATABASE_URL=PG_DATABASE_URL make migrate
+      - make migrate
       - make lint
-      - DATABASE_URL=PG_DATABASE_URL make test
+      - make test
 
   build_docker_img:
     image: plugins/docker