Added prisma schema according to the chart (#6)

* Added prisma schema according to the chart

* Added created_at and updated_at fields, changed id type to String and default it to uuid()

Author: V-Mokhun

prisma/schema.prisma

@@ -9,3 +9,52 @@ datasource db {
   provider = "postgresql"
   url      = env("DATABASE_URL")
 }
+
+model User {
+  id         String   @id @default(uuid())
+  email      String   @unique
+  name       String
+  created_at DateTime @default(now())
+  updated_at DateTime @updatedAt
+
+  work_requests WorkRequest[]
+}
+
+model Work {
+  id              String   @id @default(uuid())
+  description     String
+  start_date      DateTime
+  approval_date   DateTime
+  completion_date DateTime
+  work_type       Int
+
+  work_request WorkRequest?
+  //? If work should have more than one request, use:
+  // work_requests WorkRequest[]
+}
+
+model Authority {
+  id        String @id @default(uuid())
+  name      String
+  email     String @unique
+  work_type Int
+
+  work_requests WorkRequest[]
+}
+
+model WorkRequest {
+  rating     Float
+  created_at DateTime @default(now())
+  updated_at DateTime @updatedAt
+
+  work_id String @unique //? remove @unique if work can have more than one request
+  work    Work   @relation(fields: [work_id], references: [id])
+
+  user_id String
+  user    User   @relation(fields: [user_id], references: [id])
+
+  approving_authority_id String
+  approving_authority    Authority @relation(fields: [approving_authority_id], references: [id])
+
+  @@id([work_id, user_id])
+}