Add simple Dao to persistently store key, value pairs

build.gradle.kts

@@ -37,6 +37,7 @@ dependencies {
     implementation("com.moandjiezana.toml:toml4j:0.7.2")
     implementation(kotlin("stdlib-jdk8"))
     implementation("org.javacord:javacord:3.0.4")
+    implementation("org.mapdb:mapdb:3.0.7")
 
     testImplementation("io.kotlintest:kotlintest-runner-junit5:3.3.2")
     testImplementation("io.mockk:mockk:1.9.3")

src/main/kotlin/moe/kageru/kagebot/persistence/Dao.kt

@@ -0,0 +1,17 @@
+package moe.kageru.kagebot.persistence
+
+import org.mapdb.DBMaker
+import org.mapdb.Serializer
+
+object Dao {
+    private val db = DBMaker.fileDB("kagebot.db").fileMmapEnable().closeOnJvmShutdown().make()
+    private val strings = db.hashMap("main", Serializer.STRING, Serializer.STRING).createOrOpen()
+
+    fun store(key: String, value: String) {
+        strings[key] = value
+    }
+
+    fun get(key: String): String? {
+        return strings[key]
+    }
+}