Update database

app/src/main/java/chat/rocket/android/db/RCDatabase.kt

@@ -7,7 +7,7 @@ import chat.rocket.android.db.model.UserEntity
 
 @Database(
     entities = [UserEntity::class, ChatRoomEntity::class],
-    version = 2,
+    version = 3,
     exportSchema = true
 )
 abstract class RCDatabase : RoomDatabase() {

app/src/main/java/chat/rocket/android/db/model/UserEntity.kt

@@ -5,7 +5,7 @@ import androidx.room.Index
 import androidx.room.PrimaryKey
 
 @Entity(tableName = "users",
-        indices = [(Index(value = ["username"], unique = true))])
+        indices = [Index(value = ["username"])])
 data class UserEntity(
     @PrimaryKey override val id: String,
     var username: String? = null,