Fix wait for db/redis code

Dockerfile

@@ -17,7 +17,7 @@ RUN mkdir -p \
         /usr/share/man/man8 && \
     apt-get update && \
     apt-get install -y --no-install-recommends build-essential libpq-dev \
-      mime-support postgresql-client gettext curl && \
+      mime-support postgresql-client gettext curl netcat && \
       apt-get autoremove -y && \
       apt-get clean && \
       rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

bin/run

@@ -16,11 +16,9 @@ usage() {
 wait_for() {
   tries=0
   echo "Waiting for $1 to listen on $2..."
-  while true; do
-    [[ $tries -lt $TRIES ]] || return
-    (echo > /dev/tcp/$1/$2) >/dev/null 2>&1
-    result=
+  until nc -z $1 $2; do
     [[ $? -eq 0 ]] && return
+    [[ $tries -lt $TRIES ]] || (echo "Timed out!" && exit 1)
     sleep $SLEEP
     tries=$((tries + 1))
   done