Add an SQL DB abstraction layer

Because what self-respecting Enterprise(R) project doesn't have
one of those?

src/idz/handler/_team.ts

@@ -1,6 +1,6 @@
 import { Team } from "../model/team";
 import { Repositories } from "../repo";
-import { Id } from "../../db";
+import { Id } from "../../sql";
 
 // Bleh. This factorization is kind of messy.
 

src/idz/handler/index.ts

@@ -43,11 +43,15 @@ import { updateUserLog } from "./updateUserLog";
 import { Request } from "../request";
 import { Response } from "../response";
 import { Repositories } from "../repo";
+import { Transaction } from "../../sql";
+import { SqlRepositories } from "../db";
 
 export async function dispatch(
-  w: Repositories,
+  txn: Transaction,
   req: Request
 ): Promise<Response> {
+  const w = new SqlRepositories(txn);
+
   switch (req.type) {
     case "check_team_name_req":
       return checkTeamName(w, req);