Initial distributor implementation

appengine/cmd/dm/model/execution.go

Index: appengine/cmd/dm/model/execution.go
diff --git a/appengine/cmd/dm/model/execution.go b/appengine/cmd/dm/model/execution.go
index 7d35d6a0b4124ec86c10eafdd4b9df343a410418..6c8aa7a5569739065b1447f068d1a5b402b03fd3 100644
--- a/appengine/cmd/dm/model/execution.go
+++ b/appengine/cmd/dm/model/execution.go
@@ -10,6 +10,7 @@ import (
 
 	"github.com/luci/gae/service/datastore"
 	"github.com/luci/luci-go/appengine/cmd/dm/enums/attempt"
+	"github.com/luci/luci-go/appengine/cmd/dm/enums/execution"
 	"github.com/luci/luci-go/appengine/cmd/dm/types"
 	"github.com/luci/luci-go/common/logging"
 	"golang.org/x/net/context"
@@ -27,6 +28,9 @@ type Execution struct {
 	// added new dependencies), DM will revoke this key, making all further API
 	// access invalid.
 	ExecutionKey []byte `gae:",noindex"`
+
+	Status       execution.State
+	StatusReason string `gae:",noindex"`
 }
 
 // Done returns true iff the Execution is done (i.e. it has a blank