feat: signup service

services/signupService.js

+const db = require('../models/index');
+const User = db.User;
+
+exports.registerUser = async (userData) => {
+    try{
+        const {id,password,name,nickname,email} = userData;
+        const newUser = await User.create({
+            userId:id,
+            userPw:password,
+            name:name,
+            nickname:nickname,
+            email:email});
+        return {message:'회원가입이 완료되었습니다.', user:newUser};
+    }catch(err){
+        console.log(err);
+    }
+};
+
+exports.isIdDuplicates = async (id) =>{
+    try{
+        const findUserId = await User.findOne({
+            where:{'userId':id}
+        });
+        return findUserId !== null ? {message:'이미 존재하는 id입니다.'} : {message: '사용 가능한 id입니다.'};
+    }catch(err){
+        console.log(err);
+    }
+}
+exports.isNicknameDuplicates = async (nickname) =>{
+    try{
+        const findUserNickname = await User.findOne({
+            where:{'nickname':nickname}
+        });
+        return findUserNickname !== null ? {message:'이미 존재하는 닉네임입니다.'} : {message: '사용 가능한 닉네임입니다.'};
+    }catch(err){
+        console.log(err);
+    }
+}
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