Fixed docker file.

docker/Dockerfile

@@ -3,5 +3,5 @@ FROM openjdk:13-jdk-alpine
 RUN echo "jenkins:x:2030:100:guest:/home/jenkins:/sbin/nologin" >> /etc/passwd && \
     mkdir /home/jenkins && chmod 777 /home/jenkins && \ 
     apk update && \
-    apk add git openssh zip R bash
+    apk add git openssh zip R bash curl