Update Vagrantfile to use Xenial

Vagrantfile

@@ -1,7 +1,8 @@
 
 $script = <<SCRIPT
 apt-get update
-apt-get install -y apache2 php5 php5-sqlite php5-mysql php5-pgsql php5-gd curl unzip php5-curl php5-ldap && \
+apt-get install -y apache2 libapache2-mod-php7.0 php7.0-cli php7.0-mbstring php7.0-sqlite3 php7.0-zip \
+    php7.0-opcache php7.0-json php7.0-mysql php7.0-pgsql php7.0-ldap php7.0-gd php7.0-xml php7.0-curl && \
 apt-get clean && \
 echo "ServerName localhost" >> /etc/apache2/apache2.conf && \
 sed -ri 's/AllowOverride None/AllowOverride All/g' /etc/apache2/apache2.conf && \
@@ -25,7 +26,7 @@ SCRIPT
 Vagrant.configure("2") do |config|
 
   config.vm.define "ubuntu" do |m|
-    m.vm.box = "ubuntu/trusty64"
+    m.vm.box = "ubuntu/xenial64"
     m.vm.provision "shell", inline: $script
     m.vm.synced_folder ".", "/var/www/html", owner: "www-data", group: "www-data"
     m.vm.network :forwarded_port, guest: 80, host: 8001

doc/en_US/ubuntu-installation.markdown

@@ -9,7 +9,7 @@ Install Apache and PHP:
 ```bash
 sudo apt-get update
 sudo apt-get install -y apache2 libapache2-mod-php7.0 php7.0-cli php7.0-mbstring php7.0-sqlite3 \
-    php7.0-opcache php7.0-json php7.0-mysql php7.0-pgsql php7.0-ldap php7.0-gd php-7.0-xml
+    php7.0-opcache php7.0-json php7.0-mysql php7.0-pgsql php7.0-ldap php7.0-gd php7.0-xml
 ```
 
 Install Kanboard:

doc/en_US/vagrant.markdown

@@ -7,4 +7,4 @@ You can try Kanboard with Vagrant very easily:
 - Execute `vagrant up`
 - You can access to the application by using the URL `http://localhost:8001/`
 
-The virtual machine is based on Ubuntu 14.04 with PHP 5.5.
+The virtual machine is based on Ubuntu 16.04 with PHP 7.

doc/ru_RU/vagrant.markdown

@@ -19,7 +19,7 @@
 
 
 
-Виртуальная машина построена на Ubuntu 14.04 с PHP 5.5.
+Виртуальная машина построена на Ubuntu 16.04 с PHP 7.
 
 
 

doc/tr_TR/vagrant.markdown

@@ -7,4 +7,4 @@ Kanboard with Vagrant'ı çok kolay deneyebilirsiniz:
 - `vagrant up` yapın
 - Uygulamaya, `http://localhost:8001/` URL'sini kullanarak erişebilirsiniz.
 
-Sanal makine PHP 5.5 ile Ubuntu 14.04 üzerine kurulmuştur.
+Sanal makine PHP 7 ile Ubuntu 16.04 üzerine kurulmuştur.