Copy back config.exs, as ejabberd 21.07 uses runtime.exs

ecs/Dockerfile

@@ -10,6 +10,7 @@ RUN git clone https://github.com/processone/ejabberd.git
 WORKDIR /ejabberd
 COPY vars.config .
 RUN echo '{vsn, "'${VERSION}'.0"}.' >>vars.config
+COPY config.exs config/
 COPY rel/*exs rel/
 RUN git checkout ${VERSION/latest/HEAD} \
     && mix deps.get \

ecs/config.exs

@@ -0,0 +1,10 @@
+use Mix.Config
+
+# This is standard path in the context of ejabberd release
+config :ejabberd,
+  file: "config/ejabberd.yml",
+  log_path: 'log/ejabberd.log'
+
+# Customize Mnesia directory:
+config :mnesia,
+  dir: 'database/'