Add channels support to the Habitat type

Habitat applications can exist in the different "channels" -
like "staging", "production", "unstable" etc. Those names
can be configured by the user.

Those channels will be expressed as labels in Kubernetes.

Fixes #126

Signed-off-by: Michal Rostecki <michal@kinvolk.io>

pkg/habitat/apis/cr/v1/types.go

@@ -29,6 +29,12 @@ const (
 	HabitatNameLabel = "habitat-name"
 
 	TopologyLabel = "topology"
+
+	// HabitatChannelLabel contains the information about stability of application.
+	// Example: 'channel: production'
+	HabitatChannelLabel = "channel"
+
+	HabitatPromoteResourcePlural = "habitatpromotes"
 )
 
 type Habitat struct {
@@ -44,6 +50,9 @@ type HabitatSpec struct {
 	// Image is the Docker image of the Habitat Service.
 	Image   string  `json:"image"`
 	Service Service `json:"service"`
+	// Channel is the information about stability of the application, expressed as a label in Kubernetes.
+	// Optional.
+	Channel string `json:"channel,omitempty"`
 }
 
 type HabitatStatus struct {
@@ -94,6 +103,27 @@ const (
 	TopologyLeader     Topology = "leader"
 )
 
+type HabitatPromote struct {
+	metav1.TypeMeta   `json:",inline"`
+	metav1.ObjectMeta `json:"metadata"`
+	Spec              HabitatPromoteSpec   `json:"spec"`
+	Status            HabitatPromoteStatus `json:"status,omitempty"`
+}
+
+type HabitatPromoteSpec struct {
+	HabitatName string `json:"habitatName"`
+	OldChannel  string `json:"oldChannel"`
+	NewChannel  string `json:"newChannel"`
+	Replace     bool   `json:"replace"`
+}
+
+type HabitatPromoteStatus struct {
+	State   HabitatPromoteState `json:"state,omitempty"`
+	Message string              `json:"message,omitempty"`
+}
+
+type HabitatPromoteState string
+
 type HabitatList struct {
 	metav1.TypeMeta `json:",inline"`
 	metav1.ListMeta `json:"metadata"`