add item builder docs

guide/docs/extensions/itemBuilder.md

@@ -0,0 +1,27 @@
+## Create an itemStack
+
+Spigots ItemBuilder is often painful to use and confusing, especially for beginners. 
+
+With KSpigot itemBuilders you have an easy to use ItemBuilder and you don´t have to worry about things like itemMeta again.
+
+
+### Create a simple item
+```kotlin
+val sword = itemStack(Material.GOLDEN_SWORD) {
+    amount = 3
+    addEnchantment(Enchantment.KNOCKBACK, 2)
+    meta {
+        name = "${KColors.GOLD}Magic Sword"
+        isUnbreakable = true
+        addLore {
+            + "This sword is truly special."
+            + "Try it!"
+        }
+        customModel = 1001
+        flag(ItemFlag.HIDE_UNBREAKABLE)
+    }
+} 
+```
+### This results in following item
+
+![](img/sword.png)

guide/mkdocs.yml

@@ -37,3 +37,4 @@ nav:
   - Extensions:
       - Event listener: extensions/listener.md
       - Tasks: extensions/tasks.md
+      - Item Builder: extensions/itemBuilder.md