Update database doc

docs/README.md

@@ -30,4 +30,4 @@ Kemal means *Mature, grown up* in Turkish.
  - [Serving Static Files](./statics.md)
  - [Serving JSON API](./json.md)
  - [Middlewares](./middlewares.md)
- - [How to connect to Database](https://github.com/sdogruyol/kemal-pg-sample)
+ - [Connecting to Database](./database.md)

docs/database.md

@@ -0,0 +1,11 @@
+# Database Connection
+
+Kemal supports database connection in an easy and extensible way. Kemal uses
+a connection pool to handle all the connections meaning it's scalable by default.
+
+Currently Kemal supports Postgresql and MySQL with:
+
+- [kemal-pg](https://github.com/sdogruyol/kemal-pg)
+- [kemal-mysql](https://github.com/sdogruyol/kemal-mysql)
+
+You can check the relevant repo for samples and more info.