diff --git a/src/main/java/org/ntlab/citrusserver/entities/Account.java b/src/main/java/org/ntlab/citrusserver/entities/Account.java
new file mode 100644
index 0000000..7694b27
--- /dev/null
+++ b/src/main/java/org/ntlab/citrusserver/entities/Account.java
@@ -0,0 +1,4 @@
+package org.ntlab.citrusserver.entities;
+
+public class Account {
+}
diff --git a/src/main/java/org/ntlab/citrusserver/entities/Book.java b/src/main/java/org/ntlab/citrusserver/entities/Book.java
new file mode 100644
index 0000000..1bbf11e
--- /dev/null
+++ b/src/main/java/org/ntlab/citrusserver/entities/Book.java
@@ -0,0 +1,4 @@
+package org.ntlab.citrusserver.entities;
+
+public class Book {
+}
diff --git a/src/main/java/org/ntlab/citrusserver/entities/Todo.java b/src/main/java/org/ntlab/citrusserver/entities/Todo.java
new file mode 100644
index 0000000..95d24e9
--- /dev/null
+++ b/src/main/java/org/ntlab/citrusserver/entities/Todo.java
@@ -0,0 +1,4 @@
+package org.ntlab.citrusserver.entities;
+
+public class Todo {
+}