Group ownership completely based on users_groups relation now

Before we have only owner_id to determine group owner
With multiple owners per group we should get rid of owner_id in group.
So from now @group.owner will always be nil but
@group.owners return an actual array of users who can admin this group

app/controllers/admin/groups_controller.rb

@@ -20,9 +20,9 @@ class Admin::GroupsController < Admin::ApplicationController
   def create
     @group = Group.new(params[:group])
     @group.path = @group.name.dup.parameterize if @group.name
-    @group.owner = current_user
 
     if @group.save
+      @group.add_owner(current_user)
       redirect_to [:admin, @group], notice: 'Group was successfully created.'
     else
       render "new"
@@ -30,14 +30,7 @@ class Admin::GroupsController < Admin::ApplicationController
   end
 
   def update
-    group_params = params[:group].dup
-    owner_id =group_params.delete(:owner_id)
-
-    if owner_id
-      @group.change_owner(User.find(owner_id))
-    end
-
-    if @group.update_attributes(group_params)
+    if @group.update_attributes(params[:group])
       redirect_to [:admin, @group], notice: 'Group was successfully updated.'
     else
       render "edit"

app/controllers/groups_controller.rb

@@ -21,9 +21,9 @@ class GroupsController < ApplicationController
   def create
     @group = Group.new(params[:group])
     @group.path = @group.name.dup.parameterize if @group.name
-    @group.owner = current_user
 
     if @group.save
+      @group.add_owner(current_user)
       redirect_to @group, notice: 'Group was successfully created.'
     else
       render action: "new"

app/controllers/profiles/groups_controller.rb

@@ -8,8 +8,8 @@ class Profiles::GroupsController < ApplicationController
   def leave
     @users_group = group.users_groups.where(user_id: current_user.id).first
 
-    if group.owner == current_user
-      redirect_to(profile_groups_path, alert: "You can't leave group. You must transfer it to another owner before leaving.")
+    if group.last_owner?(current_user)
+      redirect_to(profile_groups_path, alert: "You can't leave group. You must add at least one more owner to it.")
     else
       @users_group.destroy
       redirect_to(profile_groups_path, info: "You left #{group.name} group.")

app/models/ability.rb

@@ -79,7 +79,7 @@ class Ability
         rules << project_admin_rules
       end
 
-      if project.group && project.group.owners.include?(user)
+      if project.group && project.group.has_owner?(user)
         rules << project_admin_rules
       end
 
@@ -159,7 +159,7 @@ class Ability
       end
 
       # Only group owner and administrators can manage group
-      if group.owners.include?(user) || user.admin?
+      if group.has_owner?(user) || user.admin?
         rules << [
           :manage_group,
           :manage_namespace

app/models/group.rb

@@ -16,14 +16,12 @@ class Group < Namespace
   has_many :users_groups, dependent: :destroy
   has_many :users, through: :users_groups
 
-  after_create :add_owner
-
   def human_name
     name
   end
 
   def owners
-    @owners ||= (users_groups.owners.map(&:user) << owner).uniq
+    @owners ||= users_groups.owners.map(&:user)
   end
 
   def add_users(user_ids, group_access)
@@ -36,20 +34,19 @@ class Group < Namespace
     self.users_groups.create(user_id: user.id, group_access: group_access)
   end
 
-  def change_owner(user)
-    self.owner = user
-    membership = users_groups.where(user_id: user.id).first
-
-    if membership
-      membership.update_attributes(group_access: UsersGroup::OWNER)
-    else
-      add_owner
+  def add_owner(user)
+    self.add_user(user, UsersGroup::OWNER)
   end
+
+  def has_owner?(user)
+    owners.include?(user)
   end
 
-  private
+  def last_owner?(user)
+    has_owner?(user) && owners.size == 1
+  end
 
-  def add_owner
-    self.add_users([owner.id], UsersGroup::OWNER)
+  def members
+    users_groups
   end
 end

app/models/namespace.rb

@@ -20,7 +20,7 @@ class Namespace < ActiveRecord::Base
   has_many :projects, dependent: :destroy
   belongs_to :owner, class_name: "User"
 
-  validates :owner, presence: true
+  validates :owner, presence: true, unless: ->(n) { n.type == "Group" }
   validates :name, presence: true, uniqueness: true,
             length: { within: 0..255 },
             format: { with: Gitlab::Regex.name_regex,

app/models/project.rb

@@ -249,10 +249,10 @@ class Project < ActiveRecord::Base
   end
 
   def owner
-    if namespace
-      namespace_owner
+    if group
+      group
     else
-      creator
+      namespace.try(:owner)
     end
   end
 
@@ -276,10 +276,6 @@ class Project < ActiveRecord::Base
                              end
   end
 
-  def namespace_owner
-    namespace.try(:owner)
-  end
-
   def path_with_namespace
     if namespace
       namespace.path + '/' + path

app/models/user.rb

@@ -135,7 +135,7 @@ class User < ActiveRecord::Base
       # Remove user from all groups
       user.users_groups.find_each do |membership|
         # skip owned resources
-        next if membership.group.owners.include?(user)
+        next if membership.group.last_owner?(user)
 
         return false unless membership.destroy
       end

app/services/system_hooks_service.rb

@@ -23,13 +23,15 @@ class SystemHooksService
 
     case model
     when Project
+      owner = model.owner
+
       data.merge!({
         name: model.name,
         path: model.path,
         path_with_namespace: model.path_with_namespace,
         project_id: model.id,
-        owner_name: model.owner.name,
-        owner_email: model.owner.email
+        owner_name: owner.name,
+        owner_email: owner.respond_to?(:email) ?  owner.email : nil
       })
     when User
       data.merge!({

app/views/admin/groups/index.html.haml

@@ -31,11 +31,8 @@
 
       .clearfix.light.append-bottom-10
         %span
-          %b Owner:
-          - if group.owner
-            = link_to group.owner_name, admin_user_path(group.owner)
-          - else
-            (deleted)
+          %b Members:
+          %span.badge= group.members.size
         \|
         %span
           %b Projects:

app/views/admin/groups/show.html.haml

@@ -24,26 +24,6 @@
           %strong
             = @group.description
 
-        %li
-          %span.light Owned by:
-          %strong
-            - if @group.owner
-              = link_to @group.owner_name, admin_user_path(@group.owner)
-            - else
-              (deleted)
-          .pull-right
-            = link_to "#", class: "btn btn-small change-owner-link" do
-              %i.icon-edit
-              Change owner
-        %li.change-owner-holder.hide.bgred
-          .form-holder
-            %strong.cred New Owner:
-            = form_for [:admin, @group] do |f|
-              = users_select_tag(:"group[owner_id]")
-              .prepend-top-10
-                = f.submit 'Change Owner', class: "btn btn-remove"
-                = link_to "Cancel", "#", class: "btn change-owner-cancel-link"
-
         %li
           %span.light Created at:
           %strong
@@ -92,4 +72,5 @@
               = link_to user.name, admin_user_path(user)
             %span.pull-right.light
               = member.human_access
-
+              = link_to group_users_group_path(@group, member), confirm: remove_user_from_group_message(@group, user), method: :delete, remote: true, class: "btn-tiny btn btn-remove", title: 'Remove user from group' do
+                %i.icon-minus.icon-white

app/views/admin/projects/show.html.haml

@@ -25,7 +25,7 @@
           %span.light Owned by:
           %strong
             - if @project.owner
-              = link_to @project.owner_name, admin_user_path(@project.owner)
+              = link_to @project.owner_name, [:admin, @project.owner]
             - else
               (deleted)