fix: Suppress useradd/groupadd errors (ietf-tools#4408)

Author: larseggert

docker/scripts/app-setup-debian.sh

@@ -193,14 +193,14 @@ if id -u ${USERNAME} > /dev/null 2>&1; then
 else
     # Create user
     if [ "${USER_GID}" = "automatic" ]; then
-        groupadd $USERNAME
+        groupadd --force $USERNAME
     else
-        groupadd --gid $USER_GID $USERNAME
+        groupadd --force --gid $USER_GID $USERNAME
     fi
     if [ "${USER_UID}" = "automatic" ]; then 
-        useradd -s /bin/bash --gid $USERNAME -m $USERNAME
+        useradd -s /bin/bash --gid $USERNAME -m $USERNAME || true
     else
-        useradd -s /bin/bash --uid $USER_UID --gid $USERNAME -m $USERNAME
+        useradd -s /bin/bash --uid $USER_UID --gid $USERNAME -m $USERNAME || true
     fi
 fi