Provide better diagnostic message upon project creation errors

Prevents an Error 500 when project fails to create due to invalid parameters.

See #3937

CHANGELOG

@@ -2,6 +2,7 @@ Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.3.0 (unreleased)
   - Merge when build succeeds (Zeger-Jan van de Weg)
+  - Provide better diagnostic message upon project creation errors (Stan Hu)
   - Bump gollum-lib to 4.1.0 (Stan Hu)
   - Fix broken group avatar upload under "New group" (Stan Hu)
   - Update project repositorize size and commit count during import:repos task (Stan Hu)

app/services/projects/create_service.rb

@@ -64,8 +64,10 @@ module Projects
       after_create_actions if @project.persisted?
 
       @project
-    rescue
-      @project.errors.add(:base, "Can't save project. Please try again later")
+    rescue => e
+      message = "Unable to save project: #{e.message}"
+      Rails.logger.error(message)
+      @project.errors.add(:base, message) if @project
       @project
     end