fix: ensure all build flags are consumed as an array

tests/unit/builder-dockerfile.bats

@@ -135,3 +135,31 @@ EOF
   echo "status: $status"
   assert_success
 }
+
+@test "(builder-dockerfile) run" {
+  run /bin/bash -c "dokku config:set $TEST_APP SECRET_KEY=fjdkslafjdk"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku builder:set $TEST_APP selected dockerfile"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run deploy_app dockerfile
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku ps:inspect $TEST_APP"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku run $TEST_APP env"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_contains "SECRET_KEY=fjdkslafjdk"
+}