Update readme

Author: ManticSic

README.md

@@ -8,6 +8,8 @@ This way you can immediate see if a type is registered or not. Additionally clea
 
 ## Usage
 
+### Register types
+
 You can register types to an unity container using `UnityContainerAttributeRegistration.RegisterTypeAttribute`.
 
 ```cs
@@ -19,7 +21,8 @@ namespace My.Awesome.App
     {
         public static void Main(string[] args)
         {
-            IUnityContainer container = UnityContainerPopulator.Populate();
+            UnityContainerPopulator populator = new UnityContainerPopulator();
+            IUnityContainer container = populator.Populate();
         }
     }
 
@@ -29,3 +32,77 @@ namespace My.Awesome.App
     }
 }
 ```
+
+### Register instances
+
+You can register instances to an unity container using `UnityContainerAttributeRegistration.Attribute.RegisterInstanceProviderAttribute` and `UnityContainerAttributeRegistration.Attribute.RegisterInstanceAttribute`.
+
+Classes marked with `UnityContainerAttributeRegistration.Attribute.RegisterInstanceProviderAttribute` will be instantiated using the container which should be populated with the instances.
+So you can use already registered services to create the instances, which should be later registered.
+
+```
+namespace My.Awesome.App
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            UnityContainerPopulator populator = new UnityContainerPopulator();
+            IUnityContainer container = populator.Populate();
+        }
+    }
+    
+    [RegisterInstanceProvider]
+    public class InstanceProvider
+    {
+        [RegisterInstance]
+        public string Token = "Hard coded token";
+    }
+}
+```
+
+### Using a custom container
+
+It is possible to populate a already created container.
+
+```
+namespace My.Awesome.App
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            IUnityContainer container = new UnityContainer();
+            UnityContainerPopulator populator = new UnityContainerPopulator();
+            populator.Populate(container);
+        }
+    }
+}
+```
+
+### Restrict the checked assemblies
+
+You can restrict the assemblies to check, e. g. to create a container only containing registrations of one assembly.
+
+```
+namespace My.Awesome.App
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            IAssemblyProvider assemblyProvider = new CustomAssemblyProvider();
+            UnityContainerPopulator populator = new UnityContainerPopulator(assemblyProvider);
+            IUnityContainer container = populator.Populate();
+        }
+    }
+
+    public class CustomAssemblyProvider : IAssemblyProvider
+    {
+        public IList<Assembly> GetAssemblies()
+        {
+            // return a list of assemblies to use
+        }
+    }
+}
+```