[IMP] add migration log file

to store all the migration logs. File reset at each migration.

upgrade.sh

@@ -4,6 +4,10 @@ set -euo pipefail
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
 source "${SCRIPT_DIR}/lib/common.sh"
 
+readonly LOG_FILE="${SCRIPT_DIR}/migration.log"
+rm -f "$LOG_FILE"
+exec > >(tee "$LOG_FILE") 2>&1
+
 ####################
 # USAGE & ARGUMENTS
 ####################
@@ -225,3 +229,4 @@ log_step "POST-UPGRADE PROCESSES"
 "${SCRIPT_DIR}/scripts/finalize_db.sh" "$FINALE_DB_NAME" "$FINALE_SERVICE_NAME"
 
 log_step "UPGRADE PROCESS ENDED WITH SUCCESS"
+log_info "Full logs available at: ${LOG_FILE}"