Fix alpine

Author: Chuxel

script-library/test/regression/alt.Dockerfile

@@ -10,7 +10,12 @@ FROM ${IMAGE_TO_TEST}
 # Add non-root user
 USER root
 ARG USERNAME="bort"
-RUN groupadd --gid 1001 the-borts && useradd -s /bin/bash --uid 1001 --gid 1001 -m ${USERNAME}
+RUN . /etc/os-release \
+    && if [ "${ID}" = "alpine" ] || [ "${ID_LIKE}" = "alpine" ]; then \
+        addgroup -g 1001 the-borts && adduser -D -s /bin/bash -u 1001 -G the-borts ${USERNAME}; \
+    else \
+        groupadd --gid 1001 the-borts && useradd --uid 1001 --gid 1001 -m ${USERNAME}; \
+    fi
 
 # Run non-default tests
 ARG RUN_COMMON_SCRIPT="true"