Add state

src/interfaces/state.ts

@@ -0,0 +1,9 @@
+import {IIssue} from './issue';
+
+export interface IState {
+  isIssueProcessed(issue: IIssue): boolean;
+  addIssueToProcessed(issue: IIssue): void;
+  reset(): void;
+  persist(): Promise<void>;
+  rehydrate(): Promise<void>;
+}