DOC: Add hint on code formatting

README_SETUP.md

@@ -44,6 +44,26 @@ julia> ]activate "/path/to/caosdb-julialib"
 julia> ]test
 ```
 
+## Code styling
+
+We use
+[JuliaFormatter.jl](https://github.com/domluna/JuliaFormatter.jl) for
+automatic code formatting.  Simply install JuliaFormatter by
+
+```julia-repl
+julia> ]add JuliaFormatter
+```
+
+and execute 
+
+```sh
+julia -e 'using JuliaFormatter; format(".", verbose=true)'
+```
+
+in the root directory of caosdb-julialib. You may leave out the
+`verbose=true` option if you do not wish to see which files were
+formatted.
+
 ## Documentation
 
 The documentation can be built locally using