fix(db): correct prisma initialization in seed script

prisma/seed.ts

@@ -1,8 +1,14 @@
 import { PrismaClient } from '@prisma/client'
 import { readdirSync, readFileSync } from 'fs'
 import { join, resolve } from 'path'
+import { Pool } from 'pg'
+import { PrismaPg } from '@prisma/adapter-pg'
 
-const prisma = new PrismaClient()
+const connectionString = process.env.DATABASE_URL
+const pool = new Pool({ connectionString })
+const adapter = new PrismaPg(pool)
+
+const prisma = new PrismaClient({ adapter })
 
 async function main() {
   console.log('Seeding initial maps from .canvas files...')