Updated README and improved .gitignore

.gitignore

@@ -0,0 +1,33 @@
+#### joe made this: http://goel.io/joe
+
+#### go ####
+# Binaries for programs and plugins
+*.exe
+*.dll
+*.so
+*.dylib
+
+# Test binary, build with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Project-local glide cache, RE: https://github.com/Masterminds/glide/issues/736
+.glide/
+
+#### vim ####
+# Swap
+[._]*.s[a-v][a-z]
+[._]*.sw[a-p]
+[._]s[a-v][a-z]
+[._]sw[a-p]
+
+# Session
+Session.vim
+
+# Temporary
+.netrwhist
+*~
+# Auto-generated tag files
+tags

README.md

@@ -71,10 +71,10 @@ if err := mergo.Merge(&dst, src); err != nil {
 }
 ```
 
-Also, you can merge overwriting values using MergeWithOverwrite.
+Also, you can merge overwriting values using the transformer WithOverride.
 
 ```go
-if err := mergo.MergeWithOverwrite(&dst, src); err != nil {
+if err := mergo.Merge(&dst, src, WithOverride); err != nil {
     // ...
 }
 ```
@@ -87,7 +87,7 @@ if err := mergo.Map(&dst, srcMap); err != nil {
 }
 ```
 
-Warning: if you map a struct to map, it won't do it recursively. Don't expect Mergo to map struct members of your struct as map[string]interface{}. They will be just assigned as values.
+Warning: if you map a struct to map, it won't do it recursively. Don't expect Mergo to map struct members of your struct as `map[string]interface{}`. They will be just assigned as values.
 
 More information and examples in [godoc documentation](http://godoc.org/github.com/imdario/mergo).
 
@@ -111,13 +111,10 @@ func main() {
 		A: "one",
 		B: 2,
 	}
-
 	dest := Foo{
 		A: "two",
 	}
-
 	mergo.Merge(&dest, src)
-
 	fmt.Println(dest)
 	// Will print
 	// {two 2}
@@ -126,7 +123,54 @@ func main() {
 
 Note: if test are failing due missing package, please execute:
 
-    go get gopkg.in/yaml.v1
+    go get gopkg.in/yaml.v2
+
+### Transformers
+
+Transformers allow to merge specific types differently than in the default behavior. In other words, now you can customize how some types are merged. For example, `time.Time` is a struct; it doesn't have zero value but IsZero can return true because it has fields with zero value. How can we merge a non-zero `time.Time`?
+
+```go
+package main
+
+import (
+	"fmt"
+        "reflect"
+        "time"
+)
+
+type timeTransfomer struct {
+}
+
+func (t timeTransfomer) Transformer(typ reflect.Type) func(dst, src reflect.Value) error {
+	if typ == reflect.TypeOf(time.Time{}) {
+		return func(dst, src reflect.Value) error {
+			if dst.CanSet() {
+				isZero := dst.MethodByName("IsZero")
+				result := isZero.Call([]reflect.Value{})
+				if result[0].Bool() {
+					dst.Set(src)
+				}
+			}
+		}
+	}
+	return nil
+}
+
+type Snapshot struct {
+	Time time.Time
+	// ...
+}
+
+func main() {
+	src := Snapshot{time.Now()}
+	dest := Snapshot{}
+	mergo.Merge(&dest, src, WithTransformers(timeTransfomer{}))
+	fmt.Println(dest)
+	// Will print
+	// { 2018-01-12 01:15:00 +0000 UTC m=+0.000000001 }
+}
+```
+
 
 ## Contact me