add install instructions (#2)

- We use a local registry. Therefore some extra steps are required beside the default installation commands.

README.md

@@ -1,3 +1,36 @@
 # QEDevents
 
 [![Code Style: Blue](https://img.shields.io/badge/code%20style-blue-4495d1.svg)](https://github.com/invenia/BlueStyle)
+
+
+## Installation
+
+To install the current stable version of `QEDevents.jl` you may use the standard julia package manager within the julia REPL
+
+```julia
+julia> using Pkg
+
+# add local registry, where QEDevents is registered
+julia> Pkg.Registry.add(Pkg.RegistrySpec(url="https://github.com/QEDjl-project/registry"))
+# add general registry again to have it join the local registry
+julia> Pkg.Registry.add(Pkg.RegistrySpec(url="https://github.com/JuliaRegistries/General"))
+
+julia> Pkg.add("QEDevents")
+```
+
+or you use the Pkg prompt by hitting `]` within the Julia REPL and then type
+
+```julia
+# add local registry, where QEDevents is registered
+(@v1.9) pkg> registry add https://github.com/QEDjl-project/registry
+# add general registry again to have it join the local registry
+(@v1.9) pkg> registry add https://github.com/JuliaRegistries/General
+
+(@v1.9) pkg> add QEDevents
+```
+
+To install the locally downloaded package on Windows, change to the parent directory and type within the Pkg prompt
+
+```julia
+(@v1.9) pkg> add ./QEDevents.jl
+```