feat(rules): Added LanguageCode rule

Author: ricardogobbosouza

README.md

@@ -119,6 +119,7 @@ The library can be loaded either as a standalone script, or through an [AMD](htt
 - [Iterable](docs/iterable.md)
 - [Json](docs/json.md)
 - [Label](docs/label.md)
+- [LanguageCode](docs/language-code.md)
 - [LeapDate](docs/leap-date.md)
 - [LeapYear](docs/leap-year.md)
 - [Lowercase](docs/lowercase.md)

awesome-validator.min.js

@@ -0,0 +1,17 @@
+# Language Code
+
+Validates a language code based on ISO 639:
+
+Valid values:
+
+```js
+validator.languageCode().validate('por');
+validator.languageCode().validate('eng');
+```
+
+Invalid values:
+
+```js
+validator.languageCode().validate('1');
+validator.languageCode().validate('wrong code');
+```

docs/language-code.md

@@ -40,6 +40,7 @@ export * from './int-val';
 export * from './iterable';
 export * from './json';
 export * from './label';
+export * from './language-code';
 export * from './leap-date';
 export * from './leap-year';
 export * from './lowercase';