Add schema reference using vanity url

Fixes: resumic#114

Author: stp-ip

schema/schema.go

@@ -184,6 +184,7 @@ type metaSchema struct {
 // is important to note the `ui:order` in uischema is generated based on the
 // properties order in the struct.
 type Schema struct {
+  Schema       string              `json:"$schema" schema:"description:url of JSON Schema;format:uri;example:https://schema.resumic.org/latest.json"`
 	Core         coreSchema          `json:"core"`
 	Personal     personalSchema      `json:"personal" schema:"description:sensitive informations"`
 	Work         []workSchema        `json:"work"`