Improve readme

README.md

@@ -1,3 +1,27 @@
 # Galaxus-API
 
-Small API for the web shops Galaxus and Digitec.
+Small API for the web shops Galaxus and Digitec.
+
+# Adding it to your project
+
+#### Gradle
+
+```gradle
+repositories {
+    maven {
+        name 'ubujira'
+        url 'https://maven.ubujira.dev/'
+    }
+}
+
+dependencies {
+    implementation 'dev.ubujira:Galaxus-API:0.5.0'
+}
+```
+
+# Usage
+
+```java
+GalaxusAPI galaxusAPI=new GalaxusAPI(Site.GALAXUS);
+        PriceHistory priceHistory=galaxusAPI.getPriceHistory(6329006);
+```