Added guild member add event.

events/memberadd.js

+module.exports = {
+    guildmemberadd: (client, connection) => {
+        client.on('guildMemberAdd', async (member) => {
+            let channel_db;
+            let message_db;
+            await connection.query(`SELECT message FROM welcome_message WHERE guild ='${member.guild.id}'`, function (err, result) {
+                if (err){
+                    throw err;
+                };
+                if (result.length < 1) {
+                    message_db = `Welcome to server <@${member.id}>`;
+                } else {
+                    message_db = result[0].message;
+                };
+            });
+
+            await connection.query(`SELECT channel FROM welcome_channel WHERE guild ='${member.guild.id}'`, function (err, result) {
+                if (err){
+                    throw err;
+                };
+                if (result.length < 1) {
+                    return;
+                } else {
+                    channel_db = result[0].channel;
+                    const channel = member.guild.channels.cache.get(channel_db);
+                    if (!channel) {
+                        return;
+                    };
+                    channel.send(message_db ? message_db.replace('{mention}', `${member}`).replace('{username}', `${member.user.username}`) : ``).catch(e => {
+                        return;
+                    });        
+                }
+            });
+        });
+    }
+};