Refactor acceleration tracking

backend/src/api/services/acceleration.ts

@@ -0,0 +1,20 @@
+import { query } from '../../utils/axios-query';
+import config from '../../config';
+
+export interface Acceleration {
+  txid: string,
+  feeDelta: number,
+}
+
+class AccelerationApi {
+  public async fetchAccelerations$(): Promise<Acceleration[]> {
+    if (config.MEMPOOL_SERVICES.ACCELERATIONS) {
+      const response = await query(`${config.MEMPOOL_SERVICES.API}/accelerations`);
+      return (response as Acceleration[]) || [];
+    } else {
+      return [];
+    }
+  }
+}
+
+export default new AccelerationApi();