Added support for MS SQL server driver for PHP 7.0 - requested changes:

- removed cd / && \
- added INSTALL_MSSQL to docker-compose.yml and env-example

env-example

@@ -32,6 +32,7 @@ PHP_INTERPRETER=php-fpm
 WORKSPACE_INSTALL_XDEBUG=false
 WORKSPACE_INSTALL_SOAP=false
 WORKSPACE_INSTALL_MONGO=false
+WORKSPACE_INSTALL_MSSQL=false
 WORKSPACE_INSTALL_NODE=false
 WORKSPACE_INSTALL_YARN=false
 WORKSPACE_INSTALL_DRUSH=false
@@ -54,6 +55,7 @@ WORKSPACE_SSH_PORT=2222
 
 PHP_FPM_INSTALL_XDEBUG=false
 PHP_FPM_INSTALL_MONGO=false
+PHP_FPM_INSTALL_MSSQL=false
 PHP_FPM_INSTALL_SOAP=false
 PHP_FPM_INSTALL_ZIP_ARCHIVE=false
 PHP_FPM_INSTALL_BCMATH=false