Shrinked dockerimage by removing build tools needed for twisted
diff --git a/Dockerfile b/Dockerfile
index 73d0638..3bd635f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,8 @@
 
 # Install app dependencies
 RUN apk add build-base gcc abuild binutils python-dev && \
-    pip install scapy twisted
+    pip install scapy twisted && \
+    apk del --purge build-base gcc abuild binutils python-dev
 
 # Bundle app source
 COPY voltha /voltha
@@ -13,4 +14,3 @@
 # Exposing process and default entry point
 # EXPOSE 8000
 CMD ["python", "voltha/voltha.py"]
-