Use deployment IID when saving refs

app/models/deployment.rb

@@ -102,6 +102,6 @@ def formatted_deployment_time
   private
 
   def ref_path
-    File.join(environment.ref_path, 'deployments', id.to_s)
+    File.join(environment.ref_path, 'deployments', iid.to_s)
   end
 end

app/models/environment.rb

@@ -71,8 +71,8 @@ def first_deployment_for(commit)
 
     return nil unless ref
 
-    deployment_id = ref.split('/').last
-    deployments.find(deployment_id)
+    deployment_iid = ref.split('/').last
+    deployments.find_by(iid: deployment_iid)
   end
 
   def ref_path

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -913,7 +913,7 @@ def post_assign_issues
   end
 
   describe 'GET ci_environments_status' do
-    context 'when the environment is from a forked project' do
+    context 'the environment is from a forked project' do
       let!(:forked)       { create(:project) }
       let!(:environment)  { create(:environment, project: forked) }
       let!(:deployment)   { create(:deployment, environment: environment, sha: forked.commit.id, ref: 'master') }