Allow dots in app names (closes #260)

App names may now contain dots, such as sneak.berlin: runs of
lowercase letters and numbers joined by single dots or by hyphens,
2 to 63 characters. This is Docker's rule for an image name, and the
app's image is upaas-<name>; it also keeps a dot off either end, so
the name is safe as a directory and log file name.

The new and edit app forms use the same pattern. Their old one was not
a valid regular expression under the flag browsers compile it with, so
browsers ignored it.

A test deploys an app named sneak.berlin against the fake Docker API
and checks the image and container names with Docker's own rules.

Model: opus-5-5

internal/service/deploy/deploy_images_test.go

@@ -35,12 +35,13 @@ import (
 // an image's last tag, or an untagged image by its ID, deletes the image.
 // It also answers the steps of a git clone that reports shortSHA.
 type fakeImageAPI struct {
-	mu       sync.Mutex
-	images   map[string][]string // image ID -> tags
-	shortSHA string              // the commit's short hash the clone reports
-	nextID   string              // ID of the image the next build creates
-	removed  []string            // each tag or ID removed
-	forced   bool                // whether a removal was forced
+	mu         sync.Mutex
+	images     map[string][]string // image ID -> tags
+	shortSHA   string              // the commit's short hash the clone reports
+	nextID     string              // ID of the image the next build creates
+	removed    []string            // each tag or ID removed
+	forced     bool                // whether a removal was forced
+	containers []string            // name of each named container created
 }
 
 func (api *fakeImageAPI) ServeHTTP(w http.ResponseWriter, r *http.Request) {
@@ -67,6 +68,11 @@ func (api *fakeImageAPI) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	case strings.HasSuffix(r.URL.Path, "/version"):
 		_, _ = w.Write([]byte(`{"Version":"27.3.1","ApiVersion":"1.47"}`))
 	case strings.HasSuffix(r.URL.Path, "/containers/create"):
+		// The git clone's container has no name; the app's has.
+		if containerName := r.URL.Query().Get("name"); containerName != "" {
+			api.containers = append(api.containers, containerName)
+		}
+
 		_, _ = w.Write([]byte(`{"Id":"gitcontainer"}`))
 	case strings.HasSuffix(r.URL.Path, "/logs"):
 		writeCloneOutput(w, api.shortSHA)