Add basic activity log (#141)

* Add basic activity log

* Add database migration

* Fix layout

* Fix types

---------

Co-authored-by: Sebastien Castiel <sebastien@castiel.me>

prisma/migrations/20240414135355_add_activity_log/migration.sql

@@ -0,0 +1,18 @@
+-- CreateEnum
+CREATE TYPE "ActivityType" AS ENUM ('UPDATE_GROUP', 'CREATE_EXPENSE', 'UPDATE_EXPENSE', 'DELETE_EXPENSE');
+
+-- CreateTable
+CREATE TABLE "Activity" (
+    "id" TEXT NOT NULL,
+    "groupId" TEXT NOT NULL,
+    "time" TIMESTAMP(3) NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    "activityType" "ActivityType" NOT NULL,
+    "participantId" TEXT,
+    "expenseId" TEXT,
+    "data" TEXT,
+
+    CONSTRAINT "Activity_pkey" PRIMARY KEY ("id")
+);
+
+-- AddForeignKey
+ALTER TABLE "Activity" ADD CONSTRAINT "Activity_groupId_fkey" FOREIGN KEY ("groupId") REFERENCES "Group"("id") ON DELETE RESTRICT ON UPDATE CASCADE;