Improve helper

bin/omarchy-dev-add-migration

@@ -1,5 +1,6 @@
 #!/bin/bash
 
-next_migration_date=$(git log -1 --format=%cd --date=unix)
-touch ~/.local/share/omarchy/migrations/$next_migration_date.sh
-nvim ~/.local/share/omarchy/migrations/$next_migration_date.sh
+migration_file="~/.local/share/omarchy/migrations/$(git log -1 --format=%cd --date=unix).sh"
+touch $migration_file
+nvim $migration_file
+echo -e "Run with:\nsource $migration_file"