Refactored the DB class into a regular singleton class.

backend/src/api/database-migration.ts

@@ -1,5 +1,5 @@
 import config from '../config';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 
 const sleep = (ms: number) => new Promise(res => setTimeout(res, ms));

backend/src/api/liquid/elements-parser.ts

@@ -2,7 +2,7 @@ import { IBitcoinApi } from '../bitcoin/bitcoin-api.interface';
 import bitcoinClient from '../bitcoin/bitcoin-client';
 import bitcoinSecondClient from '../bitcoin/bitcoin-second-client';
 import { Common } from '../common';
-import { DB } from '../../database';
+import DB from '../../database';
 import logger from '../../logger';
 
 class ElementsParser {

backend/src/api/pools-parser.ts

@@ -1,5 +1,4 @@
-import { readFileSync } from 'fs';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 import config from '../config';
 

backend/src/api/statistics.ts

@@ -1,5 +1,5 @@
 import memPool from './mempool';
-import { DB } from '../database';
+import DB from '../database';
 import logger from '../logger';
 
 import { Statistic, TransactionExtended, OptimizedStatistic } from '../mempool.interfaces';