add resources:hackmd npm command

packages/app/package.json

@@ -45,6 +45,7 @@
     "swagger-jsdoc": "swagger-jsdoc -o tmp/swagger.json -d config/swagger-definition.js",
     "openapi:v3": "yarn cross-env API_VERSION=3 yarn swagger-jsdoc -- \"src/server/routes/apiv3/**/*.js\" \"src/server/models/**/*.js\"",
     "openapi:v1": "yarn cross-env API_VERSION=1 yarn swagger-jsdoc -- \"src/server/*/*.js\" \"src/server/models/**/*.js\"",
+    "resources:hackmd": "yarn lerna run build --scope=@growi/hackmd",
     "resources:dummy": "true",
     "// resources:plugin": "yarn ts-node bin/generate-plugin-definitions-source.ts",
     "// resources:dl-resources": "yarn ts-node bin/download-cdn-resources.ts",