Use a more idiomatic way of building strings

String interpolation is the much preferred way to join strings in Ruby,
and also avoids issues were `:+` can sometimes not work as expected.

Worth noting:  I was getting errors on this line when running the code
locally when `@ems_id` was an integer.  It might be that in the
controller, it is passed in as a string, but this way, either works and
Ruby will convert it as needed.

app/services/ems_dashboard_service.rb

@@ -48,7 +48,7 @@ def format_data(ems_type, attributes, attr_icon, attr_url, attr_hsh)
     attr_data = []
     attributes.each do |attr|
       attr_data.push(
-        :id           => attr_hsh[attr] + '_' + @ems_id,
+        :id           => "#{attr_hsh[attr]}_#{@ems_id}",
         :iconClass    => attr_icon[attr],
         :title        => attr_hsh[attr],
         :count        => @ems.send(attr).count,