Implement PostgreSQL support and update database configuration: Migrate from SQLite to PostgreSQL by updating the Prisma schema, Docker configuration, and environment variables. Add PostgreSQL dependencies and adjust the database connection logic in the application. Enhance .gitignore to exclude PostgreSQL-related files and directories.

prisma/migrations.sqlite.backup/20251209204709_add_event_registrations/migration.sql

@@ -0,0 +1,18 @@
+-- CreateTable
+CREATE TABLE "EventRegistration" (
+    "id" TEXT NOT NULL PRIMARY KEY,
+    "userId" TEXT NOT NULL,
+    "eventId" TEXT NOT NULL,
+    "createdAt" DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    CONSTRAINT "EventRegistration_userId_fkey" FOREIGN KEY ("userId") REFERENCES "User" ("id") ON DELETE CASCADE ON UPDATE CASCADE,
+    CONSTRAINT "EventRegistration_eventId_fkey" FOREIGN KEY ("eventId") REFERENCES "Event" ("id") ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- CreateIndex
+CREATE INDEX "EventRegistration_userId_idx" ON "EventRegistration"("userId");
+
+-- CreateIndex
+CREATE INDEX "EventRegistration_eventId_idx" ON "EventRegistration"("eventId");
+
+-- CreateIndex
+CREATE UNIQUE INDEX "EventRegistration_userId_eventId_key" ON "EventRegistration"("userId", "eventId");