added option 'user'

tasks/main.yml

@@ -8,6 +8,9 @@
       {% if host_config.hostname is defined %}
           HostName {{host_config.hostname}}
       {% endif %}
+      {% if host_config.user is defined %}
+          User {{host_config.user}}
+      {% endif %}
       {% if host_config.ssh_proxy is defined %}
           ProxyCommand ssh -W localhost:{{host_config.ssh_proxy.port}} {{host_config.ssh_proxy.host}}
       {% endif %}