java.sql.SQLException: No suitable driver found for jdbc:mysql://localhost/example_db
    at java.sql.DriverManager.getConnection(DriverManager.java:689)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at org.apache.commons.dbcp.DriverManagerConnectionFactory.createConnection(DriverManagerConnectionFactory.java:75)
    at org.apache.commons.dbcp.PoolableConnectionFactory.makeObject(PoolableConnectionFactory.java:582)
    at org.apache.commons.pool.impl.GenericObjectPool.borrowObject(GenericObjectPool.java:1148)
    at org.apache.commons.dbcp.PoolingDataSource.getConnection(PoolingDataSource.java:106)
    at scalikejdbc.CommonsConnectionPool.borrow(CommonsConnectionPool.scala:43)
    at scalikejdbc.NamedDB.db$lzycompute(NamedDB.scala:33)
    at scalikejdbc.NamedDB.db(NamedDB.scala:31)
    at scalikejdbc.NamedDB.conn(NamedDB.scala:38)
    at scalikejdbc.DBConnection$class.readOnly(DBConnection.scala:190)
    at scalikejdbc.NamedDB.readOnly(NamedDB.scala:17)