fix: add fetch listener, fix pwa

.travis.yml

@@ -16,7 +16,6 @@ script:
   - chmod +x ./scripts/build.sh && ./scripts/build.sh
   - mkdocs build -v
   - find ./site -type f -name '*.html' -exec node --max_old_space_size=512 ./scripts/render_math.js {} \;
-  - touch ./site/service-worker.js
 deploy:
   provider: pages
   skip_cleanup: true

docs/service-worker.js

@@ -0,0 +1,3 @@
+this.addEventListener('fetch', function (event) {
+  //
+});

scripts/netlify_build.sh

@@ -33,4 +33,3 @@ cp ./static/extra.js docs/_static/js/extra.js
 mkdocs build -v
 
 find ./site -type f -name '*.html' -exec node --max_old_space_size=512 ./scripts/render_math.js {} \;
-touch ./site/service-worker.js