dev: add convenience copy-file bin and fix data path used by plugin

.devcontainer/20_init_plugin

@@ -18,7 +18,7 @@ main() {
   # built in the Dockerfile
   PLUGIN_NAME="$(source /tmp/.env && echo "$PLUGIN_NAME")"
   PLUGIN_VARIABLE="$(source /tmp/.env && echo "$PLUGIN_VARIABLE")"
-  dokku config:set --global "${PLUGIN_VARIABLE}_HOST_ROOT=${SERVICE_HOST_ROOT}"
+  echo "export ${PLUGIN_VARIABLE}_HOST_ROOT=${SERVICE_HOST_ROOT}/$PLUGIN_NAME" > /etc/default/dokku
 }
 
 main "$@"

.devcontainer/Dockerfile

@@ -12,6 +12,7 @@ RUN apt-get install --no-install-recommends -y build-essential && \
 ADD https://raw.githubusercontent.com/dokku/dokku/master/tests/dhparam.pem /mnt/dokku/etc/nginx/dhparam.pem
 
 COPY .devcontainer/20_init_plugin /etc/my_init.d/20_init_plugin
+COPY .devcontainer/bin/ /usr/local/bin/
 
 COPY . .
 

.devcontainer/bin/copy-file

@@ -0,0 +1,8 @@
+#!/usr/bin/env bash
+
+main() {
+  PLUGIN_NAME="$(source /tmp/.env && echo "$PLUGIN_NAME")"
+  cp "$1" "/var/lib/dokku/plugins/enabled/$PLUGIN_NAME/$1"
+}
+
+main "$@"