Fix `docker/entrypoint.sh`

`docker/entrypoint.sh` was updated to fix errors that results in a
container that runs on a locally built Ferdi Server image.

Fixes that were made:

- shebang was changed to `#!/bin/sh` as the Node Alpine image does not
  have `bash`, therefore the container cannot start because of the error
  "/usr/local/bin/docker-entrypoint.sh: exec: line 8: /entrypoint.sh:
  not found";
- `if` condition was updated to make it more portable so it works with
  non-Bash shells;
- `su-exec` command was updated to remove the redundant `#!/bin/bash`
  from the end of the line as it was causing the error "Error: Cannot
  find module '/app/server.js#!/bin/bash'".

Additional code optimization changes:

- tabs were replaced with spaces;
- optimizations to avoid code duplication:
  - new variable `key_file` was added to hold the path to the Ferdi app
    key file;
  - the function `print_app_key_message` was added to print the
    informational message about the app key.

1 files changed, 21 insertions, 11 deletions

diff --git a/docker/entrypoint.sh b/docker/entrypoint.sh
index 2a91839..2e58abc 100755
--- a/docker/entrypoint.sh
+++ b/docker/entrypoint.sh
@@ -1,4 +1,4 @@
-#!/bin/bash
+#!/bin/sh
 
 cat << EOL
 -------------------------------------
@@ -14,21 +14,31 @@ Support our Open Collective at:
 https://opencollective.com/getferdi/
 EOL
 
+key_file="${DATA_DIR}/FERDI_APP_KEY.txt"
+
+print_app_key_message() {
+  app_key=$1
+  printf '**** App key is %s. ' ${app_key}
+  printf 'You can modify `%s` to update the app key ****\n' ${key_file}
+}
+
 # Create APP key if needed
-if [[ -z ${APP_KEY} && ! -f "${DATA_DIR}/FERDI_APP_KEY.txt" ]]; then
-        echo "**** Generating Ferdi-server app key for first run ****"
-        adonis key:generate
-        APP_KEY=$(grep APP_KEY .env | cut -d '=' -f2)
-        echo "${APP_KEY}" > "${DATA_DIR}/FERDI_APP_KEY.txt"
-        echo "**** App Key set to $APP_KEY you can modify FERDI_APP_KEY.txt to update your key ****"
-else APP_KEY=$(cat "${DATA_DIR}/FERDI_APP_KEY.txt")
-        echo "**** App Key set to $APP_KEY you can modify FERDI_APP_KEY.txt to update your key ****"
+if [ -z ${APP_KEY} ] && [ ! -f ${key_file} ]
+then
+  echo '**** Generating Ferdi-server app key for first run ****'
+  adonis key:generate
+  APP_KEY=$(grep APP_KEY .env | cut -d '=' -f2)
+  echo ${APP_KEY} > ${key_file}
+  print_app_key_message ${APP_KEY}
+else
+  APP_KEY=$(cat ${key_file})
+  print_app_key_message ${APP_KEY}
 fi
 
 export APP_KEY
 
 node ace migration:run --force
 
-chown -R "${PUID:-1000}":"${PGID:-1000}" "$DATA_DIR" /app
+chown -R "${PUID:-1000}":"${PGID:-1000}" "${DATA_DIR}" /app
 
-su-exec "${PUID:-1000}":"${PGID:-1000}" node server.js#!/bin/bash
+su-exec "${PUID:-1000}":"${PGID:-1000}" node server.js