Order commits by committed_at and id

This needs to be done that way, because the committed_at can be null for some pretty old commits.

CHANGELOG

-v7.14.0 (unreleased)
+v7.14.1
+  - Fix commits ordering
+
+v7.14.0
   - Truncate commit messages after subject line in table
   - Adjust CI config to support Docker executors
   - Added Application Settings

app/models/project.rb

@@ -28,7 +28,7 @@
 class Project < ActiveRecord::Base
   include ProjectStatus
-  has_many :commits, ->() { order(:committed_at) }, dependent: :destroy
+  has_many :commits, ->() { order(:committed_at, :id) }, dependent: :destroy
   has_many :builds, through: :commits, dependent: :destroy
   has_many :runner_projects, dependent: :destroy
   has_many :runners, through: :runner_projects

db/migrate/20150824202238_add_index_for_committed_at_and_id.rb

+class AddIndexForCommittedAtAndId < ActiveRecord::Migration
+  def up
+    add_index :commits, [:project_id, :committed_at, :id]
+  end
+end

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
-ActiveRecord::Schema.define(version: 20150819162227) do
+ActiveRecord::Schema.define(version: 20150824202238) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -62,6 +62,7 @@ ActiveRecord::Schema.define(version: 20150819162227) do
     t.datetime "committed_at"
   end
+  add_index "commits", ["project_id", "committed_at", "id"], name: "index_commits_on_project_id_and_committed_at_and_id", using: :btree
   add_index "commits", ["project_id", "committed_at"], name: "index_commits_on_project_id_and_committed_at", using: :btree
   add_index "commits", ["project_id", "sha"], name: "index_commits_on_project_id_and_sha", using: :btree
   add_index "commits", ["project_id"], name: "index_commits_on_project_id", using: :btree