The common and utility functions are grouped in a file named Extension.kt (you can specify any name you want). It contains top-level functions that can be used anywhere in the project.
Complete the Extension.kt file:
/** * Builds the insert query for the specified message */ fun insertQuery(m: Message): Messages.(UpdateBuilder<*>) -> Unit = { if (m.id != null) it[id] = m.id it[content] = m.content it[location] = m.location } /** * Create the message object from Result row * @return message */ fun ResultRow.getMessage() = Message(this[Messages.content], this[Messages.location], this[Messages.id]) // Other extension functions