debug discordHook logics, session fix.

- DiscordHook normal respond is not defined
- add MariadbSessionStorage

common/src/main/kotlin/space/mori/chzzk_bot/common/Connector.kt

@@ -34,7 +34,8 @@ object Connector {
             TimerConfigs,
             LiveStatuses,
             SongLists,
-            SongConfigs
+            SongConfigs,
+            Sessions
         )
 
         transaction {

common/src/main/kotlin/space/mori/chzzk_bot/common/models/Session.kt

@@ -0,0 +1,18 @@
+package space.mori.chzzk_bot.common.models
+
+import org.jetbrains.exposed.dao.IntEntity
+import org.jetbrains.exposed.dao.IntEntityClass
+import org.jetbrains.exposed.dao.id.EntityID
+import org.jetbrains.exposed.dao.id.IntIdTable
+
+object Sessions: IntIdTable("session") {
+    val key = text("key")
+    val value = text("value")
+}
+
+class Session(id: EntityID<Int>) : IntEntity(id) {
+    companion object : IntEntityClass<Session>(Sessions)
+
+    var key by Sessions.key
+    var value by Sessions.value
+}