dev add reason entity

src/main/java/ru/soune/nocopy/exception/ModerationReasonInUseException.java

@@ -0,0 +1,17 @@
+package ru.soune.nocopy.exception;
+
+import lombok.Getter;
+
+@Getter
+public class ModerationReasonInUseException extends RuntimeException {
+  private final Long reasonId;
+  private final Long usageCount;
+
+  public ModerationReasonInUseException(Long reasonId, Long usageCount) {
+    super(String.format("Cannot delete moderation reason %d because it is used by %d files",
+            reasonId, usageCount));
+    this.reasonId = reasonId;
+    this.usageCount = usageCount;
+  }
+
+}

src/main/java/ru/soune/nocopy/exception/ModerationReasonNotFoundException.java

@@ -0,0 +1,7 @@
+package ru.soune.nocopy.exception;
+
+public class ModerationReasonNotFoundException extends RuntimeException {
+    public ModerationReasonNotFoundException(Long id) {
+        super("Moderation reason not found with id: " + id);
+    }
+}