Init V4 community edition (#2265)

* Init V4 community edition

* Init V4 community edition

ent/schema/metadata.go

@@ -0,0 +1,48 @@
+package schema
+
+import (
+	"entgo.io/ent"
+	"entgo.io/ent/schema/edge"
+	"entgo.io/ent/schema/field"
+	"entgo.io/ent/schema/index"
+)
+
+// Metadata holds the schema definition for the Metadata entity.
+type Metadata struct {
+	ent.Schema
+}
+
+// Fields of the Metadata.
+func (Metadata) Fields() []ent.Field {
+	return []ent.Field{
+		field.String("name"),
+		field.Text("value"),
+		field.Int("file_id"),
+		field.Bool("is_public").
+			Default(false),
+	}
+}
+
+// Edges of the Metadata.
+func (Metadata) Edges() []ent.Edge {
+	return []ent.Edge{
+		edge.From("file", File.Type).
+			Ref("metadata").
+			Field("file_id").
+			Required().
+			Unique(),
+	}
+}
+
+func (Metadata) Indexes() []ent.Index {
+	return []ent.Index{
+		index.Fields("file_id", "name").
+			Unique(),
+	}
+}
+
+func (Metadata) Mixin() []ent.Mixin {
+	return []ent.Mixin{
+		CommonMixin{},
+	}
+}