feat: move all build steps to multi-stage docker image build

.drone.yml

@@ -6,24 +6,6 @@ trigger:
     - push
 
 steps:
-  - name: theme
-    image: kolaente/toolbox
-    pull: true
-    group: build-static
-    commands:
-      - mkdir themes/vikunja -p
-      - cd themes/vikunja
-      - wget https://dl.vikunja.io/theme/vikunja-theme.tar.gz
-      - tar -xzf vikunja-theme.tar.gz
-
-  - name: build
-    image: klakegg/hugo:0.99.1
-    pull: true
-    commands:
-      - rm -rf public
-      - hugo
-      - cat public/index.html
-
   - name: docker
     image: plugins/docker
     pull: true

Dockerfile

@@ -1,3 +1,20 @@
+FROM kolaente/toolbox AS build-theme
+
+COPY . /web
+WORKDIR /web
+RUN mkdir /web/themes/vikunja -p && \
+  cd /web/themes/vikunja && \
+  wget https://dl.vikunja.io/theme/vikunja-theme.tar.gz && \
+  tar -xzf vikunja-theme.tar.gz
+
+FROM klakegg/hugo:0.99.1 as builder
+
+COPY . /web
+WORKDIR /web
+COPY --from=build-theme /web/themes /web/themes
+
+RUN rm -rf public && hugo
+
 FROM nginx
-ADD public /usr/share/nginx/html
+COPY --from=builder /web/public /usr/share/nginx/html
 ADD nginx.conf /etc/nginx/nginx.conf