Truncate commit messages after subject line in table

Commit messages are now additionally truncated after the first line.
Before, a commit message's body was attached behind the subject which
made messages hardly readable in some cases.

CHANGELOG

 v7.14.0 (unreleased)
+  - Truncate commit messages after subject line in table
   - Adjust CI config to support Docker executors
   
 v7.13.1

app/helpers/commits_helper.rb

@@ -15,4 +15,8 @@ module CommitsHelper
   def commit_link(commit)
     link_to(commit.short_sha, project_ref_commit_path(commit.project, commit.ref, commit.sha))
   end
+
+  def truncate_first_line(message, length = 50)
+    truncate(message.lines.first.chomp, length: length)
+  end
 end

app/views/commits/_commit.html.haml

@@ -11,7 +11,7 @@
       %strong #{commit.short_sha}
   %td.build-message
-    %span= truncate(commit.git_commit_message, length: 50)
+    %span= truncate_first_line(commit.git_commit_message)
   %td.build-branch
     - unless @ref
@@ -30,4 +30,3 @@
     %td.coverage
       - if commit.coverage
         #{commit.coverage}%
-