Update readme to explain how to install

README.md

@@ -10,6 +10,7 @@
 [Support Me on Ko-fi](https://ko-fi.com/Z8Z5DYWA)
 
 ### xNode
+
 Thinking of developing a node-based plugin? Then this is for you. You can download it as an archive and unpack to a new unity project, or connect it as git submodule.
 
 xNode is super userfriendly, intuitive and will help you reap the benefits of node graphs in no time.
@@ -19,24 +20,39 @@ With a minimal footprint, it is ideal as a base for custom state machines, dialo
   <img src="https://user-images.githubusercontent.com/6402525/53689100-3821e680-3d4e-11e9-8440-e68bd802bfd9.png">
 </p>
 
+### Installing with Unity Package Manager
+
+To install this project as a dependency using the Unity Package Manager,
+add the following line to your project's `manifest.json`:
+
+```
+"com.github.siccity.xnode": "git+https://github.com/siccity/xNode",
+```
+
+Then, to access the `XNode` namespace from your code, make sure you have a valid [Assembly Definition](https://docs.unity3d.com/Manual/ScriptCompilationAssemblyDefinitionFiles.html) set up,
+with `xNode` set as an Assembly Reference.
+
 ### Key features
-* Lightweight in runtime
-* Very little boilerplate code
-* Strong separation of editor and runtime code
-* No runtime reflection (unless you need to edit/build node graphs at runtime. In this case, all reflection is cached.)
-* Does not rely on any 3rd party plugins
-* Custom node inspector code is very similar to regular custom inspector code
-* Supported from Unity 5.3 and up
+
+- Lightweight in runtime
+- Very little boilerplate code
+- Strong separation of editor and runtime code
+- No runtime reflection (unless you need to edit/build node graphs at runtime. In this case, all reflection is cached.)
+- Does not rely on any 3rd party plugins
+- Custom node inspector code is very similar to regular custom inspector code
+- Supported from Unity 5.3 and up
 
 ### Wiki
-* [Getting started](https://github.com/Siccity/xNode/wiki/Getting%20Started) - create your very first node node and graph
-* [Examples branch](https://github.com/Siccity/xNode/tree/examples) - look at other small projects
+
+- [Getting started](https://github.com/Siccity/xNode/wiki/Getting%20Started) - create your very first node node and graph
+- [Examples branch](https://github.com/Siccity/xNode/tree/examples) - look at other small projects
 
 ### Node example:
+
 ```csharp
 // public classes deriving from Node are registered as nodes for use within a graph
 public class MathNode : Node {
-    // Adding [Input] or [Output] is all you need to do to register a field as a valid port on your node 
+    // Adding [Input] or [Output] is all you need to do to register a field as a valid port on your node
     [Input] public float a;
     [Input] public float b;
     // The value of an output node field is not used for anything, but could be used for caching output results
@@ -46,7 +62,7 @@ public class MathNode : Node {
     // The value of 'mathType' will be displayed on the node in an editable format, similar to the inspector
     public MathType mathType = MathType.Add;
     public enum MathType { Add, Subtract, Multiply, Divide}
-    
+
     // GetValue should be overridden to return a value for any specified output port
     public override object GetValue(NodePort port) {