Provide better email subject lines from email on push service

If one commit is pushed, display the commit message in the subject
line. Otherwise display the number of commits pushed to the repository.

CHANGELOG

@@ -37,6 +37,7 @@ v 7.0.0
   - Remove wall feature (no data loss - you can take it from database)
   - Dont expose user emails via API unless you are admin 
   - Detect issues closed by Merge Request description
+  - Better email subject lines from email on push service (Alex Elman)
 v 6.9.2
   - Revert the commit that broke the LDAP user filter

app/mailers/emails/projects.rb

@@ -25,13 +25,15 @@ module Emails
       @branch  = branch
       if @commits.length > 1
         @target_url = project_compare_url(@project, from: @commits.first, to: @commits.last)
+        @subject = "#{@commits.length} new commits pushed to repository"
       else
         @target_url = project_commit_url(@project, @commits.first)
+        @subject = @commits.first.title
       end
       mail(from: sender(author_id),
            cc: recipient,
-           subject: subject("New push to repository"))
+           subject: subject(@subject))
     end
   end
 end

spec/mailers/notify_spec.rb

@@ -537,7 +537,7 @@ describe Notify do
     end
     it 'has the correct subject' do
-      should have_subject /New push to repository/
+      should have_subject /#{commits.length} new commits pushed to repository/
     end
     it 'includes commits list' do
@@ -573,7 +573,7 @@ describe Notify do
     end
     it 'has the correct subject' do
-      should have_subject /New push to repository/
+      should have_subject /#{commits.first.title}/
     end
     it 'includes commits list' do