Add more docs and example

README.md

@@ -13,6 +13,36 @@ Puddle is a tiny generic resource pool library for Go that uses the standard con
 * High performance
 * 100% test coverage
 
+## Example Usage
+
+```go
+constructor := func(context.Context) (interface{}, error) {
+  return net.Dial("tcp", "127.0.0.1:8080")
+}
+destructor := func(value interface{}) {
+  value.(net.Conn).Close()
+}
+maxPoolSize := 10
+
+pool := puddle.NewPool(constructor, destructor, maxPoolSize)
+
+// Acquire resource from the pool.
+res, err := pool.Acquire(context.Background())
+if err != nil {
+  // ...
+}
+
+// Use resource.
+_, err = res.Value().(net.Conn).Write([]byte{1})
+if err != nil {
+  // ...
+}
+
+// Release when done.
+res.Release()
+
+```
+
 ## License
 
 MIT