Convert all tables in database to utf8mb4. Fix #928

server/setup/knex/migrations/20200824160149_convert_to_utf8mb4.js

@@ -0,0 +1,17 @@
+
+exports.up = function(knex, Promise) {
+  return knex.raw('SELECT table_name FROM information_schema.tables WHERE table_schema = ?', [knex.client.database()])
+    .then(function(tablas) {
+       let sql="";
+       tablas=tablas[0];
+       for(let i=0; i<tablas.length; i++) {
+	 sql+="ALTER TABLE "+tablas[i].table_name+" CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci;";
+       }
+       //console.log(sql);
+       return knex.raw(sql);
+    });
+};
+
+exports.down = function(knex, Promise) {
+  
+};