Implement basic logic for /status endpoint

Currently it gets a list of connected users from websocket session store
and popuplates array of statuses:

[{"userID":"83947155491913829","status":"online","icon":"","message":""},
 {"userID":"85008081418715239","status":"online","icon":"","message":""}]

messaging/rest/router.go

@@ -27,6 +27,7 @@ func MountRoutes() func(chi.Router) {
 			handlers.NewChannel(Channel{}.New()).MountRoutes(r)
 			handlers.NewMessage(Message{}.New()).MountRoutes(r)
 			handlers.NewSearch(Search{}.New()).MountRoutes(r)
+			handlers.NewStatus(Status{}.New()).MountRoutes(r)
 			handlers.NewCommands(Commands{}.New()).MountRoutes(r)
 		})
 	}

messaging/rest/status.go

@@ -6,6 +6,7 @@ import (
 	"github.com/pkg/errors"
 
 	"github.com/crusttech/crust/messaging/rest/request"
+	"github.com/crusttech/crust/messaging/websocket"
 )
 
 var _ = errors.Wrap
@@ -19,7 +20,22 @@ func (Status) New() *Status {
 }
 
 func (ctrl *Status) List(ctx context.Context, r *request.StatusList) (interface{}, error) {
-	return nil, errors.New("Not implemented: Status.list")
+	type userStatus struct {
+		UserID  uint64 `json:"userID,string"`
+		Status  string `json:"present"`
+		Icon    string `json:"icon"`
+		Message string `json:"message"`
+	}
+
+	out := []userStatus{}
+	for _, userID := range websocket.GetConnectedUsers() {
+		out = append(out, userStatus{
+			UserID: userID,
+			Status: "online",
+		})
+	}
+
+	return out, nil
 }
 
 func (ctrl *Status) Set(ctx context.Context, r *request.StatusSet) (interface{}, error) {

messaging/websocket/session_store.go

@@ -61,3 +61,18 @@ func (s *Store) Delete(id uint64) {
 	defer s.Unlock()
 	delete(s.Sessions, id)
 }
+
+func GetConnectedUsers() []uint64 {
+	var chk = map[uint64]bool{}
+
+	store.Walk(func(session *Session) {
+		chk[session.user.Identity()] = true
+	})
+
+	var out = make([]uint64, 0)
+	for ID := range chk {
+		out = append(out, ID)
+	}
+
+	return out
+}