Add a jenkins image

.drone.yml

@@ -11,6 +11,14 @@ steps:
       - name: docker_socket
         path: /var/run/docker.sock
 
+  - name: build jenkins-ubuntu
+    image: docker
+    commands:
+      - docker build -t erki/jenkins-ubuntu:latest - < jenkins-ubuntu.Dockerfile
+    volumes:
+      - name: docker_socket
+        path: /var/run/docker.sock
+
   - name: notify
     image: plugins/matrix
     settings:
@@ -25,7 +33,7 @@ steps:
     when:
       status:
       - failure
-        
+
 volumes:
   - name: docker_socket
     host:

jenkins-ubuntu.Dockerfile

@@ -0,0 +1,6 @@
+FROM ubuntu:20.04
+
+ENV DEBIAN_FRONTEND noninteractive
+
+RUN apt-get update -y
+RUN apt-get install -y --no-install-recommends git build-essential cmake ninja-build python3 python3-pip default-jre