add zig package manager help to readme

readme.md

@@ -8,6 +8,29 @@ It seams that most other websocket implementations are using zlib for deflate.
 [zlib 1.2.13 Manual](https://www.zlib.net/manual.html)
 
 
+### Link
+There is empty zig project (made with 'zig init-exe') in [example/exe](example/exe) which illustrates how to link zlib library using zig package manager.
+
+Add dependency in build.zig.zon:
+```zig
+    .dependencies = .{
+        .zlib = .{
+            .url = "https://github.com/ianic/zig-zlib/archive/9186b0f5fdfd6c29cd04f7ada7b0113fe1f63611.tar.gz",
+            .hash = "122001cc3da638f9315f08fb51fe5aace68c254b59bcac3457e20d746565bad7fe04",
+        },
+    },
+```
+In build.zig link 'z' library and 'zlib' module:
+```zig
+    // Link z library and zlib module.
+    exe.linkLibrary(b.dependency("zlib", .{
+        .target = target,
+        .optimize = optimize,
+    }).artifact("z"));
+    exe.addModule("zlib", zlib.module("zlib"));
+```
+
+
 ### Notes
 
 get zlib source into zlib folder: