Docs improvements

docs/content/doc/development/config.md

@@ -0,0 +1,41 @@
+---
+date: "2019-02-12:00:00+02:00"
+title: "Configuration Options"
+draft: false
+type: "doc"
+menu:
+  sidebar:
+    parent: "development"
+---
+
+# Configuration options
+
+All configuration variables are declared in the `config` package.
+It uses [viper](https://github.com/spf13/viper) under the hood to handle setting defaults and parsing config files.
+Viper handles parsing all different configuration sources.
+
+## Adding new config options
+
+To make handling configuration parameters a bit easier, we introduced a `Key` string type in the `config` package which 
+you can call directly to get a config value.
+
+To add a new config option, you should add a new key const to `pkg/config/config.go` and possibly a default value.
+Default values should always enable the feature to work or turn it off completely if it always needs
+additional configuration.
+
+Make sure to also add the new config option to the default config file (`config.yml.sample` at the root of the repository) 
+with an explanatory comment to make sure it is well documented.
+Then run `mage generate-docs` to generate the configuration docs from the sample file.
+
+## Getting Configuration Values
+
+To retreive a configured value call the key with a getter for the type you need.
+For example:
+
+{{< highlight golang >}}
+if config.CacheEnabled.GetBool() {
+	// Do something with enabled caches
+}
+{{< /highlight >}}
+
+Take a look at the methods declared on the type to see what's available.