Add rescript build command in dockerfile (#568)

Author: ahangarha

.controlplane/Dockerfile

@@ -28,6 +28,7 @@ ENV NODE_ENV=production
 # compiling assets requires any value for ENV of SECRET_KEY_BASE
 ENV SECRET_KEY_BASE=NOT_USED_NON_BLANK
 
+RUN yarn res:build
 RUN rails react_on_rails:locale
 RUN rails assets:precompile