Added jenkins slave agent port settings through the environmental variable JENKINS_SLAVE_AGENT_PORT
diff --git a/Dockerfile b/Dockerfile
index b22290b..f142acf 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -3,6 +3,7 @@
 RUN apt-get update && apt-get install -y wget git curl zip && rm -rf /var/lib/apt/lists/*
 
 ENV JENKINS_HOME /var/jenkins_home
+ENV JENKINS_SLAVE_AGENT_PORT 50000
 
 # Jenkins is ran with user `jenkins`, uid = 1000
 # If you bind mount a volume from host/volume from a data container,