readme update

README.md

@@ -1,3 +1,24 @@
 # faller
 
 Small logging library.
+
+## Installation
+
+Run:
+```bash
+zig fetch --save git+https://git.pascalzittlau.de/pzittlau/faller.git
+```
+
+Then put this in `build.zig`:
+```zig
+const faller = b.dependency("faller", .{
+    .target = target,
+    .optimize = optimize,
+    // Other options
+});
+mod.addImport("faller", faller.module("faller"));
+```
+
+## License
+
+Apache 2.0