Remove simple code duplication in members controllers

app/controllers/admin/teams/members_controller.rb

 class Admin::Teams::MembersController < Admin::Teams::ApplicationController
   def new
-    @users = User.active
-    @users = @users.not_in_team(user_team) if user_team.members.any?
+    @users = User.potential_team_members(user_team)
     @users = UserDecorator.decorate @users
   end

app/controllers/teams/members_controller.rb

@@ -7,8 +7,7 @@ class Teams::MembersController < Teams::ApplicationController
   end
   def new
-    @users = User.active
-    @users = @users.not_in_team(user_team) if user_team.members.any?
+    @users = User.potential_team_members(user_team)
     @users = UserDecorator.decorate @users
   end

app/models/user.rb

@@ -91,6 +91,7 @@ class User < ActiveRecord::Base
   scope :alphabetically, order('name ASC')
   scope :in_team, ->(team){ where(id: team.member_ids) }
   scope :not_in_team, ->(team){ where('users.id NOT IN (:ids)', ids: team.member_ids) }
+  scope :potential_team_members, ->(team) { team.members.any? ? active : active.not_in_team(team) }
   #
   # Class methods