Set sort order for getAllUnsent() from the oldest

app/src/main/java/chat/rocket/android/chatroom/service/MessageService.kt

@@ -7,6 +7,7 @@ import chat.rocket.android.server.domain.MessagesRepository
 import chat.rocket.android.server.infraestructure.ConnectionManagerFactory
 import chat.rocket.common.RocketChatException
 import chat.rocket.core.internal.rest.sendMessage
+import chat.rocket.core.model.Message
 import dagger.android.AndroidInjection
 import kotlinx.coroutines.experimental.CommonPool
 import kotlinx.coroutines.experimental.launch
@@ -50,6 +51,7 @@ class MessageService : JobService() {
 
     private suspend fun retrySendingMessages(currentServer: String) {
         val temporaryMessages = messageRepository.getAllUnsent()
+            .sortedWith(compareBy(Message::timestamp))
         if (temporaryMessages.isNotEmpty()) {
             val connectionManager = factory.create(currentServer)
             val client = connectionManager.client