docker-compose variables and setup

setup/templates/steps/root.html

@@ -0,0 +1,8 @@
+{% call macros.panel("info", "Step 0 - Set root path") %}
+<p>Before starting root path must be set</p>
+
+<div class="form-group">
+  <label>Root path: </label>
+  <input class="form-control" type="text" name="root" placeholder="/mailu">
+</div>
+{% endcall %}