diff --git a/.gitignore b/.gitignore
index 7ff52f6..d470ccd 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,6 +6,7 @@
 /vendor/
 /bin/
 /composer.phar
+/log/capistrano.log
 app/config/parameters.yml
 .vagrant
 .idea
diff --git a/README.md b/README.md
index 781a4de..028a57b 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,17 @@ Also make sure there is a directory `/project/dir/` available which is writable
 
 If you want to deploy the app you will need capistrano-symfony:
 
-`gem install capistrano-symfony --pre-release`
+```
+gem install airbrussh
+gem install capistrano
+gem install capistrano-composer
+gem install capistrano-harrow
+gem install capistrano-symfony
+gem install i18n
+gem install net-scp
+gem install net-ssh
+gem install sshkit
+```
  
 ### Vhost
 
diff --git a/Vagrantfile b/Vagrantfile
index 3c0752a..432ca83 100644
--- a/Vagrantfile
+++ b/Vagrantfile
@@ -61,4 +61,6 @@ Vagrant.configure(VAGRANTFILE_API_VERSION) do |config|
     config.vm.provision :shell, path: "provision/windows.sh"
   end
 
+  config.ssh.forward_agent = true
+
 end
diff --git a/app/config/deployment/deploy.rb b/app/config/deployment/deploy.rb
index 9d09ce3..c44fdab 100644
--- a/app/config/deployment/deploy.rb
+++ b/app/config/deployment/deploy.rb
@@ -1,5 +1,4 @@
 # config valid only for current version of Capistrano
-lock '3.4.0'
 
 set :application, 'grouphub.api'
 set :repo_url, 'git@github.com:SURFnet/grouphub.api.git'
diff --git a/src/AppBundle/Manager/MembershipManager.php b/src/AppBundle/Manager/MembershipManager.php
index 0fa2005..31128d5 100644
--- a/src/AppBundle/Manager/MembershipManager.php
+++ b/src/AppBundle/Manager/MembershipManager.php
@@ -2,9 +2,11 @@
 
 namespace AppBundle\Manager;
 
+use AppBundle\Entity\User;
 use AppBundle\Entity\UserInGroup;
 use AppBundle\Event\GroupEvent;
 use Doctrine\Bundle\DoctrineBundle\Registry;
+use Doctrine\ORM\EntityManager;
 use Doctrine\ORM\Query\Expr;
 use Doctrine\ORM\QueryBuilder;
 use Doctrine\ORM\Tools\Pagination\Paginator;
@@ -132,7 +134,17 @@ public function findMemberships(
      */
     public function addMembership(UserInGroup $userInGroup, $message)
     {
+        /** @var EntityManager $manager */
         $manager = $this->doctrine->getManager();
+        $existingUser = $manager->getRepository(UserInGroup::class)->findOneBy([
+            'user' => $userInGroup->getUser(),
+            'group' => $userInGroup->getGroup()
+        ]);
+
+        if ($existingUser instanceof UserInGroup) {
+            return;
+        }
+
         $manager->persist($userInGroup);
         $manager->flush();
 
diff --git a/src/AppBundle/Manager/UserManager.php b/src/AppBundle/Manager/UserManager.php
index 540d82d..8bc8d3b 100644
--- a/src/AppBundle/Manager/UserManager.php
+++ b/src/AppBundle/Manager/UserManager.php
@@ -3,6 +3,7 @@
 namespace AppBundle\Manager;
 
 use AppBundle\Entity\User;
+use AppBundle\Entity\UserAnnotation;
 use AppBundle\Event\UserEvent;
 use Doctrine\Bundle\DoctrineBundle\Registry;
 use Doctrine\ORM\Query\Expr;
@@ -54,6 +55,8 @@ public function findUser($id)
      * @param string $loginName
      *
      * @return User|User[]
+     *
+     * @SuppressWarnings(PHPMD.CyclomaticComplexity)
      */
     public function findUsers(
         $query = null,
@@ -66,6 +69,8 @@ public function findUsers(
         /** @var QueryBuilder $qb */
         $qb = $this->doctrine->getRepository('AppBundle:User')->createQueryBuilder('u');
 
+        $qb->leftJoin(UserAnnotation::class, 'a', Expr\Join::LEFT_JOIN, 'a.user = u.id');
+
         if ($sort === 'name') {
             $sort = new Expr\OrderBy('u.lastName');
             $sort->add('u.firstName');
@@ -86,12 +91,20 @@ public function findUsers(
         if (!empty($query)) {
             $terms = explode(' ', $query);
 
+            if (!empty($terms)) {
+                $qb->setParameter('annotation_type_email', 'email');
+            }
+
             foreach ($terms as $i => $term) {
                 $qb->andWhere(
                     $qb->expr()->orX(
                         $qb->expr()->like('u.firstName', ':term' . $i),
                         $qb->expr()->like('u.lastName', ':term' . $i),
-                        $qb->expr()->like('u.loginName', ':term' . $i)
+                        $qb->expr()->like('u.loginName', ':term' . $i),
+                        $qb->expr()->andX(
+                            $qb->expr()->like('a.attribute', ':annotation_type_email'),
+                            $qb->expr()->like('a.value', ':term' . $i)
+                        )
                     )
                 );