update README

README.md

@@ -1,2 +1,29 @@
 # CAST IN THE NAME OF PHP, YE NOT GUILTY
+## ABOUT
 - you can cast any values in the weak mode manner, even if you are in the strict mode (strict_types=1)
+
+## INSTALL
+```
+composer require sj-i/php-cast
+```
+
+## USAGE
+
+```
+use PhpCast\Cast;
+
+// int(1)
+$int_value = Cast::toInt('1');
+// string(1) "1"
+$string_value = Cast::toString(1);
+// float(1)
+$float_value = Cast::toFloat(1);
+// bool(true)
+$bool_value = Cast::toBool(1);
+
+// TypeError
+$int_value = Cast::toInt('a');
+```
+
+## LICENSE
+MIT