docs: update readme

README.md

@@ -6,6 +6,35 @@ A minimalistic and straightforward **bash dependency manager**.
 
 ### Usage
 
+#### bashdep::install
+
+You can distinguish between regular dependencies and dev-dependencies when defining the URL.
+Dev-dependencies ends with `@dev`
+
+```bash
+DEPENDENCIES=(
+  "https://github.com/[...]/download/0.17.0/bashunit"
+  "https://github.com/[...]/download/0.1/dumper.sh@dev"
+)
+
+bashdep::install "${DEPENDENCIES[@]}"
+```
+
+#### bashdep::setup
+
+Alternately, you can configure the default values of bashdep using the setup function.
+
+- `dir=string`: set the default destination directory. Default: `lib`
+- `dev-dir=string`: set the development destination directory. Default: `lib/dev`
+- `silent=bool`: if true, no progress text will be shown during installation. Default: `false`
+
+```bash
+bashdep::setup dir="lib" dev-dir="src/dev" silent=false
+bashdep::install "${DEPENDENCIES[@]}"
+```
+
+### Demo
+
 Usage example from
 [Chemaclass/bash-skeleton](https://github.com/Chemaclass/bash-skeleton/blob/main/install-dependencies.sh)