doc: add page for codegen feature-flags (#1023)

doc/md/code-gen.md

@@ -230,3 +230,9 @@ func EnsureStructTag(name string) gen.Hook {
 	}
 }
 ```
+
+## Feature Flags
+
+The `entc` package provides a collection of code-generation features that be added or removed using flags.
+
+For more information, please see the [features-flags page](features.md).

doc/md/features.md

@@ -0,0 +1,74 @@
+---
+id: feature-flags
+title: Feature Flags
+sidebar_label: Feature Flags
+---
+
+The framework provides a collection of code-generation features that be added or removed using flags.
+
+## Usage
+
+Feature flags can be provided either by CLI flags or as arguments to the `gen` package. 
+
+#### CLI
+
+```console
+go run github.com/facebook/ent/cmd/ent generate --feature privacy,entql ./ent/schema
+```
+
+#### Go
+
+```go
+// +build ignore
+
+package main
+
+import (
+	"log"
+	"text/template"
+
+	"github.com/facebook/ent/entc"
+	"github.com/facebook/ent/entc/gen"
+)
+
+func main() {
+	err := entc.Generate("./schema", &gen.Config{
+		Features: []*gen.Feature{
+			gen.FeaturePrivacy,
+			gen.FeatureEntQL,
+		},
+		Templates: []*gen.Template{
+			gen.MustParse(gen.NewTemplate("static").
+				Funcs(template.FuncMap{"title": strings.ToTitle}).
+				ParseFiles("template/static.tmpl")),
+		},
+	})
+	if err != nil {
+		log.Fatalf("running ent codegen: %v", err)
+	}
+}
+```
+
+## List of Features
+
+#### Privacy Layer
+
+The privacy layer allows configuring privacy policy for queries and mutations of entities in the database.
+
+This option can be added to projects using the `--feature privacy` flag, and its full documentation exists
+in the [privacy page](privacy.md).
+
+#### EntQL Filtering
+
+The `entql` option provides a generic and dynamic filtering capability at runtime for the different query builders.
+
+This option can be added to projects using the `--feature entql` flag, and more information about it exists
+in the [privacy page](privacy.md#multi-tenancy).
+
+#### Auto-Solve Merge Conflicts
+
+The `schema/snapshot` option tells `entc` (ent codegen) to store a snapshot of the latest schema in an internal package,
+and use it to automatically solve merge conflicts when user's schema can't be built.
+
+This option can be added to projects using the `--feature schema/snapshot` flag, but please see
+[facebook/ent/issues/852](https://github.com/facebook/ent/issues/852) to get more context about it.

doc/website/sidebars.json

@@ -32,7 +32,8 @@
       "graphql",
       "sql-integration",
       "testing",
-      "faq"
+      "faq",
+      "feature-flags"
     ]
   }
 }