DOC: Add a dummy function with documentation

docs/make.jl

+using Documenter, CaosDB
+
+makedocs(sitename="CaosDB.jl Documentation")

docs/src/index.md

+# CaosDB.jl documentation
+
+This will be the index of the documentation of the CaosDB Julia client
+library.
+
+```@docs
+dummy_func(x)
+```

src/CaosDB.jl

 module CaosDB
 
-greet() = print("Hello World!")
+export dummy_func
+
+"""
+    dummy_func(x)
+
+Returns double the number `x` plus `1`.
+"""
+dummy_func(x) = 2x + 1
 
 end # module