add db interaction layer

src/database/DatabaseFactory.kt

@@ -0,0 +1,46 @@
+package com.kmalbz.database
+
+import com.typesafe.config.ConfigFactory
+import com.zaxxer.hikari.*
+import io.ktor.config.HoconApplicationConfig
+import io.ktor.util.KtorExperimentalAPI
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import org.jetbrains.exposed.sql.*
+import org.jetbrains.exposed.sql.transactions.transaction
+
+object DatabaseFactory {
+
+    @KtorExperimentalAPI
+    private val appConfig = HoconApplicationConfig(ConfigFactory.load())
+    @KtorExperimentalAPI
+    private val dbUrl = appConfig.property("db.jdbcUrl").getString()
+    @KtorExperimentalAPI
+    private val dbUser = appConfig.property("db.dbUser").getString()
+    @KtorExperimentalAPI
+    private val dbPassword = appConfig.property("db.dbPassword").getString()
+
+    @KtorExperimentalAPI
+    fun init() {
+        Database.connect(hikari())
+    }
+
+    @KtorExperimentalAPI
+    private fun hikari(): HikariDataSource {
+        val config = HikariConfig()
+        config.driverClassName = "org.postgresql.Driver"
+        config.jdbcUrl = dbUrl
+        config.username = dbUser
+        config.password = dbPassword
+        config.maximumPoolSize = 3
+        config.isAutoCommit = false
+        config.transactionIsolation = "TRANSACTION_REPEATABLE_READ"
+        config.validate()
+        return HikariDataSource(config)
+    }
+
+    suspend fun <T> dbQuery(block: () -> T): T =
+        withContext(Dispatchers.IO) {
+            transaction { block() }
+        }
+}