Fix: Enable building of nginx image on master

.gitlab-ci.yml

@@ -71,10 +71,12 @@ build nginx image:
   stage: build
   interruptible: true
   except:
+    refs:
+      - schedules
     changes:
-      - "**/README.md"
+      - README.md
   only:
-    - rewrite
+    - master
   variables:
     DOCKER_TLS_CERTDIR: "/certs"
     GIT_SUBMODULE_STRATEGY: recursive
@@ -100,6 +102,7 @@ build nginx image:
 
 
 build app image:
+  image: docker:latest
   stage: build
   except:
     refs:
@@ -113,7 +116,6 @@ build app image:
     GIT_SUBMODULE_STRATEGY: recursive
   tags:
     - docker
-  image: docker:latest
   services:
     - docker:dind
   before_script: []