update app.json, install-packages.sh

app.json

@@ -25,9 +25,9 @@
       "description": "A password seed is used by password hash generator. ",
       "generator": "secret"
     },
-    "INSTALL_PLUGINS": {
-      "description": "Comma-separated list of plugin package names to install.",
-      "value": "growi-plugin-lsx,growi-plugin-pukiwiki-like-linker,growi-plugin-attachment-refs",
+    "ADDITIONAL_PACKAGES": {
+      "description": "Space-separated list of npm package names to install.",
+      "value": "growi-plugin-lsx growi-plugin-pukiwiki-like-linker growi-plugin-attachment-refs react-images react-motion",
       "required": false
     }
   },

bin/heroku/install-packages.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+yarn add -D $ADDITIONAL_PACKAGES

bin/heroku/install-plugins.sh

@@ -1,7 +0,0 @@
-#!/bin/sh
-
-export IFS=","
-
-for plugin in $INSTALL_PLUGINS; do
-  yarn add $plugin
-done