add entities and db migrations

src/main/kotlin/com/restapi/controllers/Entities.kt

@@ -6,6 +6,7 @@ import com.fasterxml.jackson.databind.JsonDeserializer
 import com.fasterxml.jackson.databind.JsonNode
 import com.fasterxml.jackson.databind.annotation.JsonDeserialize
 import com.restapi.domain.*
+import com.restapi.domain.PurchaseOrder
 import com.restapi.domain.Session.currentUser
 import com.restapi.domain.Session.database
 import com.restapi.domain.Session.findDataModelByEntityAndUniqId
@@ -371,4 +372,17 @@ object Entities {
     } catch (e: Exception) {
         false
     }
+}
+
+object PurchaseOrder {
+    fun get(ctx :Context){
+        val id = ctx.pathParam("id")
+        val po = database.find(PurchaseOrder::class.java, id) ?: throw NotFoundResponse("po not found for $id")
+
+        ctx.json(po)
+    }
+    fun create(ctx :Context){
+        val po = ctx.bodyAsClass<PurchaseOrder>()
+        database.save(po)
+    }
 }