add - #160 슬랙 관련 상수 추가

src/main/java/sopt/org/hmh/domain/slack/constant/AttachmentColor.java

@@ -0,0 +1,15 @@
+package sopt.org.hmh.domain.slack;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum AttachmentColor {
+
+    GREEN("98ff98"),
+    ORANGE("ffb700"),
+    RED("ff0000");
+
+    private final String color;
+}

src/main/java/sopt/org/hmh/domain/slack/constant/SlackStatus.java

@@ -0,0 +1,16 @@
+package sopt.org.hmh.domain.slack;
+
+import lombok.Getter;
+import lombok.RequiredArgsConstructor;
+
+@Getter
+@RequiredArgsConstructor
+public enum SlackStatus {
+
+    NEW_USER_SIGNUP(AttachmentColor.GREEN.getColor(), "🎉 신규 유저 회원 가입 발생"),
+    INTERNAL_ERROR(AttachmentColor.ORANGE.getColor(), "🚨 서버 내부 에러 발생"),
+    CLIENT_ERROR(AttachmentColor.GREEN.getColor(), "😭 서버 오류 발생");
+
+    private final String color;
+    private final String title;
+}