Add `Group#add_*` convenience methods

Encapsulates the logic for `Gitlab::Access::WHATEVER` levels.

app/models/group.rb

@@ -76,8 +76,24 @@ class Group < Namespace
     add_users([user], access_level, current_user)
   end
+  def add_guest(user, current_user = nil)
+    add_user(user, Gitlab::Access::GUEST, current_user)
+  end
+
+  def add_reporter(user, current_user = nil)
+    add_user(user, Gitlab::Access::REPORTER, current_user)
+  end
+
+  def add_developer(user, current_user = nil)
+    add_user(user, Gitlab::Access::DEVELOPER, current_user)
+  end
+
+  def add_master(user, current_user = nil)
+    add_user(user, Gitlab::Access::MASTER, current_user)
+  end
+
   def add_owner(user, current_user = nil)
-    self.add_user(user, Gitlab::Access::OWNER, current_user)
+    add_user(user, Gitlab::Access::OWNER, current_user)
   end
   def has_owner?(user)

features/steps/admin/groups.rb

@@ -58,7 +58,7 @@ class Spinach::Features::AdminGroups < Spinach::FeatureSteps
   end
   step 'we have user "John Doe" in group' do
-    current_group.add_user(user_john, Gitlab::Access::REPORTER)
+    current_group.add_reporter(user_john)
   end
   step 'I remove user "John Doe" from group' do

features/steps/admin/users.rb

@@ -79,7 +79,7 @@ class Spinach::Features::AdminUsers < Spinach::FeatureSteps
     project.team << [user, :developer]
     group = create(:group)
-    group.add_user(user, Gitlab::Access::DEVELOPER)
+    group.add_developer(user)
   end
   step 'click on "Mike" link' do

features/steps/explore/groups.rb

@@ -19,7 +19,7 @@ class Spinach::Features::ExploreGroups < Spinach::FeatureSteps
   step '"John Doe" is owner of group "TestGroup"' do
     group = Group.find_by(name: "TestGroup") || create(:group, name: "TestGroup")
     user = create(:user, name: "John Doe")
-    group.add_user(user, Gitlab::Access::OWNER)
+    group.add_owner(user)
   end
   step 'I visit group "TestGroup" page' do

features/steps/invites.rb

@@ -6,7 +6,7 @@ class Spinach::Features::Invites < Spinach::FeatureSteps
   step '"John Doe" has invited "user@example.com" to group "Owned"' do
     user = User.find_by(name: "John Doe")
     group = Group.find_by(name: "Owned")
-    group.add_user("user@example.com", Gitlab::Access::DEVELOPER, user)
+    group.add_developer("user@example.com", user)
   end
   step 'I visit the invitation page' do

spec/finders/projects_finder_spec.rb

@@ -39,7 +39,7 @@ describe ProjectsFinder do
   end
   context 'authenticated, group member' do
-    before { group.add_user(user, Gitlab::Access::DEVELOPER) }
+    before { group.add_developer(user) }
     subject { ProjectsFinder.new.execute(user, group: group) }

spec/lib/gitlab/markdown/user_reference_filter_spec.rb

@@ -77,7 +77,7 @@ module Gitlab::Markdown
       context 'that the current user can read' do
         before do
-          group.add_user(user, Gitlab::Access::DEVELOPER)
+          group.add_developer(user)
         end
         it 'links to the Group' do

spec/models/hooks/system_hook_spec.rb

@@ -101,7 +101,7 @@ describe SystemHook do
     it 'group member create hook' do
       group = create(:group)
       user = create(:user)
-      group.add_user(user, Gitlab::Access::MASTER)
+      group.add_master(user)
       expect(WebMock).to have_requested(:post, @system_hook.url).with(
         body: /user_add_to_group/,
         headers: { 'Content-Type'=>'application/json', 'X-Gitlab-Event'=>'System Hook' }
@@ -111,7 +111,7 @@ describe SystemHook do
     it 'group member destroy hook' do
       group = create(:group)
       user = create(:user)
-      group.add_user(user, Gitlab::Access::MASTER)
+      group.add_master(user)
       group.group_members.destroy_all
       expect(WebMock).to have_requested(:post, @system_hook.url).with(
         body: /user_remove_from_group/,

spec/models/project_team_spec.rb

@@ -37,9 +37,9 @@ describe ProjectTeam do
     let(:project) { create(:empty_project, group: group) }
     before do
-      group.add_user(master, Gitlab::Access::MASTER)
-      group.add_user(reporter, Gitlab::Access::REPORTER)
-      group.add_user(guest, Gitlab::Access::GUEST)
+      group.add_master(master)
+      group.add_reporter(reporter)
+      group.add_guest(guest)
       # If user is a group and a project member - GitLab uses highest permission
       # So we add group guest as master and add group master as guest

spec/requests/api/groups_spec.rb

@@ -135,7 +135,7 @@ describe API::API, api: true  do
       it "should not remove a group if not an owner" do
         user4 = create(:user)
-        group1.add_user(user4, Gitlab::Access::MASTER)
+        group1.add_master(user4)
         delete api("/groups/#{group1.id}", user3)
         expect(response.status).to eq(403)
       end

spec/support/markdown_feature.rb

@@ -17,7 +17,7 @@ class MarkdownFeature
   def group
     unless @group
       @group = create(:group)
-      @group.add_user(user, Gitlab::Access::DEVELOPER)
+      @group.add_developer(user)
     end
     @group