update readme

Author: Perlmint

README.md

@@ -1 +1,18 @@
-# i18next-korean-postposition-processor
+# i18next-korean-postposition-processor
+
+i18next post-processor for processing korean postposition - `을/를`, `이/가`, `은/는`, `으로/로`, `과/와`.
+
+This processor can handle korean character or arabic number(without decimal mark).
+
+## Setup
+
+```javascript
+import KoreanPostProcessor from 'i18next-korean-postposition-processor';
+
+i18next.use(KoreanPostProcessor);
+```
+
+## Translation text
+```
+{{some_value}}[[를]] 수정했다.
+```