update docs

README.md

@@ -8,6 +8,13 @@ Will marshal to a blank string if null. Blank string input produces a null Strin
 
 `UnmarshalJSON` supports `sql.NullString` input. 
 
+### Int
+A nullable int64. 
+
+Unlike null.String, null.Int will marshal to null if null. Zero input will not produce a null Int. 
+
+`UnmarshalJSON` supports `sql.NullInt64` input. 
+
 ### Bugs
 `json`'s `",omitempty"` struct tag does not work correctly right now. It will never omit a null or empty String. This should be [fixed in Go 1.4](https://code.google.com/p/go/issues/detail?id=4357).
 

int.go

@@ -6,7 +6,7 @@ import (
 	"strconv"
 )
 
-// Int is a nullable int.
+// Int is a nullable int64.
 type Int struct {
 	sql.NullInt64
 }
@@ -80,6 +80,7 @@ func (i Int) MarshalText() ([]byte, error) {
 	return []byte(strconv.FormatInt(i.Int64, 10)), nil
 }
 
+// Pointer returns a pointer to this Int's value, or a nil pointer if this Int is null.
 func (i Int) Pointer() *int64 {
 	if !i.Valid {
 		return nil