[BridgeAbstract] Add 'getMaintainer' function

BridgeAbstract.md

@@ -4,6 +4,7 @@ To create a new Bridge extending `BridgeAbstract` you must specify some [basic m
 
 - [`collectData`](#the-collectdata-function) (**required**)
 - [`getDescription`](#the-getdescription-function)
+- [`getMaintainer`](#the-getmaintainer-function)
 - [`getName`](#the-getname-function)
 - [`getURI`](#the-geturi-function)
 
@@ -182,6 +183,18 @@ This function returns the description of a bridge.
 	}
 ```
 
+## The `getMaintainer` function
+
+This function returns the maintainer name of a bridge.
+
+**Notice:** **RSS-Bridge** will by default return `const MAINTAINER` which is defined in the bridge, so you only have to implement this function if you require different behavior!
+
+```PHP
+	public function getMaintainer(){
+		return self::MAINTAINER;
+	}
+```
+
 ## The `getName` function
 
 This function returns the name of a bridge..