Create a todo on failing MR build

When a build fails for a commit, create a todo for the author of the
merge request that commit is the HEAD of. If the commit isn't the HEAD
commit of any MR, don't do anything. If there already is a todo for that
user and MR, don't do anything.

Current limitations:
- This isn't configurable by project.
- The author of a merge request might not be the person who pushed the
  breaking commit.

1 files changed, 7 insertions, 2 deletions

diff --git a/app/models/todo.rb b/app/models/todo.rb
index f8b59fe4126..3a091373329 100644
--- a/app/models/todo.rb
+++ b/app/models/todo.rb
@@ -1,6 +1,7 @@
 class Todo < ActiveRecord::Base
-  ASSIGNED  = 1
-  MENTIONED = 2
+  ASSIGNED     = 1
+  MENTIONED    = 2
+  BUILD_FAILED = 3
 
   belongs_to :author, class_name: "User"
   belongs_to :note
@@ -28,6 +29,10 @@ class Todo < ActiveRecord::Base
     state :done
   end
 
+  def build_failed?
+    action == BUILD_FAILED
+  end
+
   def body
     if note.present?
       note.note