Custom scalar docs

docs/config.yml

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   main:
     - name: Tutorials
       identifier: tutorial
+      weight: 10
+    - name: Reference
+      identifier: reference

docs/content/reference/scalars.md

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+---
+title: "Custom Scalars"
+description: Using custom graphql types in golang
+date: 2018-03-17T13:06:47+11:00
+menu: {"main": {"parent": "reference"}}
+---
+
+There are two different ways to implement scalars in gqlgen, depending on your need.
+
+
+## With user defined types
+For user defined types you can implement the graphql.Marshal and graphql.Unmarshal interfaces and they will be called.
+
+```go
+package mypkg
+
+import (
+	"fmt"
+	"io"
+	"strings"
+)
+
+type YesNo bool
+
+// UnmarshalGQL implements the graphql.Marshaler interface
+func (y *YesNo) UnmarshalGQL(v interface{}) error {
+	yes, ok := v.(string)
+	if !ok {
+		return fmt.Errorf("points must be strings")
+	}
+
+	if yes == "yes" {
+		*y = true
+	} else {
+		*y = false
+	}
+	return nil
+}
+
+// MarshalGQL implements the graphql.Marshaler interface
+func (y YesNo) MarshalGQL(w io.Writer) {
+	if y {
+		w.Write([]byte(`"yes"`))
+	} else {
+		w.Write([]byte(`"no"`))
+	}
+}
+```
+
+and then in types.json point to the name without the Marshal|Unmarshal in front:
+```json
+{
+    "YesNo": "github.com/me/mypkg.YesNo"
+}
+```
+
+
+## Custom scalars for types you don't control
+
+Sometimes you cant add methods to a type because its in another repo, part of the standard 
+library (eg string or time.Time). To do this we can build an external marshaler:
+
+```go
+package mypkg
+
+import (
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/vektah/gqlgen/graphql"
+)
+
+
+func MarshalMyCustomBooleanScalar(b bool) graphql.Marshaler {
+	return graphql.WriterFunc(func(w io.Writer) {
+		if b {
+			w.Write([]byte("true"))
+		} else {
+			w.Write([]byte("false"))
+		}
+	})
+}
+
+func UnmarshalMyCustomBooleanScalar(v interface{}) (bool, error) {
+	switch v := v.(type) {
+	case string:
+		return "true" == strings.ToLower(v), nil
+	case int:
+		return v != 0, nil
+	case bool:
+		return v, nil
+	default:
+		return false, fmt.Errorf("%T is not a bool", v)
+	}
+}
+```
+
+and then in types.json point to the name without the Marshal|Unmarshal in front:
+```json
+{
+    "MyCustomBooleanScalar": "github.com/me/mypkg.MyCustomBooleanScalar"
+}
+```
+
+see the [example/scalars](https://github.com/vektah/gqlgen/tree/master/example/scalars) package for more examples.

docs/static/main.css

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 header {
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 }
 
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 ul.submenu {
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+    margin-bottom: 0;
 }
 
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docs/static/syntax.css

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