refine Dockerfile

Dockerfile

@@ -1,15 +1,15 @@
 FROM alpine
 
-ENV SERVER_ADDR 0.0.0.0
-ENV SERVER_PORT 51348
-ENV PASSWORD    psw
-ENV METHOD      aes-128-ctr
-ENV PROTOCOL    auth_aes128_md5
+ENV SERVER_ADDR     0.0.0.0
+ENV SERVER_PORT     51348
+ENV PASSWORD        psw
+ENV METHOD          aes-128-ctr
+ENV PROTOCOL        auth_aes128_md5
 ENV PROTOCOLPARAM   32
-ENV OBFS        tls1.2_ticket_auth_compatible
-ENV TIMEOUT     300
-ENV DNS_ADDR    8.8.8.8
-ENV DNS_ADDR_2  8.8.4.4
+ENV OBFS            tls1.2_ticket_auth_compatible
+ENV TIMEOUT         300
+ENV DNS_ADDR        8.8.8.8
+ENV DNS_ADDR_2      8.8.4.4
 
 
 RUN apk update \
@@ -30,4 +30,5 @@ RUN wget --no-check-certificate https://github.com/shadowsocksr/shadowsocksr/arc
 WORKDIR ~/shadowsocksr/shadowsocks
 
 
+EXPOSE 51348
 CMD python ~/shadowsocksr/shadowsocks/server.py -p $SERVER_PORT -k $PASSWORD -m $METHOD -O $PROTOCOL -o $OBFS -G $PROTOCOLPARAM