fix iso code validation (#686)

cmd/server/assets/admin/realms/new.html

@@ -43,8 +43,9 @@ <h1>New realm</h1>
             {{template "errorable" $realm.ErrorsFor "regionCode"}}
             <small class="form-text text-muted">
               Used in creating deep link SMS for multi-helath authority apps. Region should
-              be <a href="https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes">ISO 3166-1 country codes and ISO 3166-2 subdivision codes</a> where applicable.
-              For example, Washington State would be <code>US-WA</code>.
+              be <a href="https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes">ISO 3166-1 country codes and (optionally) ISO 3166-2 subdivision codes</a> where applicable.
+              For example, Washington State would be <code>US-WA</code>, and Canada would be <code>CA</code>. The region code should be scoped to the authority of the public health
+              system represented by this verification system.
             </small>
           </div>
 

pkg/database/realm.go

@@ -254,8 +254,10 @@ func (r *Realm) BeforeSave(tx *gorm.DB) error {
 			r.AddError("regionCode", "cannot be blank when using EN Express")
 		} else {
 			parts := strings.Split(r.RegionCode, "-")
-			if len(parts) != 2 {
-				r.AddError("regionCode", "must be formated like 'region-subregion', 2 characters dash 2 or 3 characters")
+			if lp := len(parts); lp != 2 {
+				if lp == 1 && len(parts[0]) != 2 {
+					r.AddError("regionCode", "must be formated like 'region' (2 characters) or 'region-subregion' (2 characters dash 2 or 3 characters)")
+				}
 			} else {
 				if len(parts[0]) != 2 {
 					r.AddError("regionCode", "first part must be exactly 2 characters in length")