Extend /surveys/ endpoint to include reference gauge * Add a subselection to the sql query in models/surveys.go which similiar to the `bottleneck_geoserver` view assumes that the reference gauge is the same for each survey result. * Maintain rights infos.

# documentation
**/README*
**/docs
**/*.md

# backend binary
cmd/gemma/gemma

# Dependency directories
**/node_modules

# local dotenv environment variables file
client/.env.local

# Tags tables
**/TAGS