diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 8bf068e..61b28c9 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -132,6 +132,11 @@ docker-build-fe:
   script:
     - docker-compose build waecm_g4_fe
     - docker save -o waecm_g4_fe ${DOCKER_USER}/${ASSIGNMENT}-fe
+  cache:
+    key: $CI_COMMIT_REF_SLUG-$CI_PROJECT_DIR
+    paths:
+      - frontend/node_modules/
+    policy: pull
   extends:
     - .docker-build
     - .docker-setup
diff --git a/frontend/.dockerignore b/frontend/.dockerignore
index de4d1f0..1521c8b 100644
--- a/frontend/.dockerignore
+++ b/frontend/.dockerignore
@@ -1,2 +1 @@
 dist
-node_modules
diff --git a/frontend/Dockerfile b/frontend/Dockerfile
index e7389d9..0b875ad 100644
--- a/frontend/Dockerfile
+++ b/frontend/Dockerfile
@@ -6,6 +6,6 @@ WORKDIR /app
 
 COPY . .
 
-RUN npm install
+RUN npm install && npm install chokidar --save
 
 ENTRYPOINT npm run -- ng serve --host 0.0.0.0 --port 4200
diff --git a/frontend/src/app/validators/keywords.validator.ts b/frontend/src/app/validators/keywords.validator.ts
index e505fea..26cf40f 100644
--- a/frontend/src/app/validators/keywords.validator.ts
+++ b/frontend/src/app/validators/keywords.validator.ts
@@ -1,7 +1,7 @@
 import {AbstractControl} from '@angular/forms';
 
 export function keywordsValidator(control: AbstractControl): { [key: string]: any } | null {
-  if (control.value === undefined) {
+  if (control.value === null) {
     return null;
   }
   let split: string[];