Also set dns args for redis addon

part of #307

src/addons.js

@@ -638,6 +638,8 @@ function setupRedis(app, options, callback) {
                 --net-alias ${redisName} \
                 -m 100m \
                 --memory-swap 150m \
+                --dns 172.18.0.1 \
+                --dns-search=. \
                 -v ${redisVarsFile}:/etc/redis/redis_vars.sh:ro \
                 -v ${redisDataDir}:/var/lib/redis:rw \
                 --read-only -v /tmp -v /run ${tag}`;