Don't hardcode IDs in migration spec

Signed-off-by: Rémy Coutable <remy@rymai.me>

spec/migrations/20190924152703_migrate_issue_trackers_data_spec.rb

@@ -14,28 +14,28 @@ describe MigrateIssueTrackersData, :migration do
     }
   end
   let!(:jira_service) do
-    services.create(id: 10, type: 'JiraService', properties: properties, category: 'issue_tracker')
+    services.create(type: 'JiraService', properties: properties, category: 'issue_tracker')
   end
   let!(:jira_service_nil) do
-    services.create(id: 11, type: 'JiraService', properties: nil, category: 'issue_tracker')
+    services.create(type: 'JiraService', properties: nil, category: 'issue_tracker')
   end
   let!(:bugzilla_service) do
-    services.create(id: 12, type: 'BugzillaService', properties: properties, category: 'issue_tracker')
+    services.create(type: 'BugzillaService', properties: properties, category: 'issue_tracker')
   end
   let!(:youtrack_service) do
-    services.create(id: 13, type: 'YoutrackService', properties: properties, category: 'issue_tracker')
+    services.create(type: 'YoutrackService', properties: properties, category: 'issue_tracker')
   end
   let!(:youtrack_service_empty) do
-    services.create(id: 14, type: 'YoutrackService', properties: '', category: 'issue_tracker')
+    services.create(type: 'YoutrackService', properties: '', category: 'issue_tracker')
   end
   let!(:gitlab_service) do
-    services.create(id: 15, type: 'GitlabIssueTrackerService', properties: properties, category: 'issue_tracker')
+    services.create(type: 'GitlabIssueTrackerService', properties: properties, category: 'issue_tracker')
   end
   let!(:gitlab_service_empty) do
-    services.create(id: 16, type: 'GitlabIssueTrackerService', properties: {}, category: 'issue_tracker')
+    services.create(type: 'GitlabIssueTrackerService', properties: {}, category: 'issue_tracker')
   end
   let!(:other_service) do
-    services.create(id: 17, type: 'OtherService', properties: properties, category: 'other_category')
+    services.create(type: 'OtherService', properties: properties, category: 'other_category')
   end
 
   before do