improve README

README.md

@@ -46,6 +46,58 @@ The template provides a simple [Dockerfile](build/Dockerfile) and [script](scrip
 
 ### Define a new model
 
+1. Install sea-orm-cli first
+
+```
+cargo install sea-orm-cli
+```
+
+2. Define migration in [migrations](src/migrations)
+
+```rust
+#[derive(Iden)]
+pub enum User { // Identifiers for User table
+    Table, // Table Identifier
+    Id, // Id Column Identifier
+    Name, // Name Column Identifier
+    Password, // Password Column Identifier
+}
+
+impl MigrationName for Migration {
+    fn name(&self) -> &str {
+        "m20220804_000001_create_user_table" // A migration name `m$(date +%Y%m%d)_8digitno_desc`
+    }
+}
+
+#[async_trait::async_trait]
+impl MigrationTrait for Migration {
+    async fn up(&self, manager: & sea_orm_migration::SchemaManager) ->  Result<(),sea_orm::DbErr> {
+        manager.create_table(
+            Table::create()
+                .table(User::Table) // Table
+                .col(ColumnDef::new(User::Id).integer().primary_key().auto_increment().not_null()) // And each col
+                .col(ColumnDef::new(User::Name).string().unique_key().not_null())
+                .col(ColumnDef::new(User::Password).string().not_null())
+                .to_owned()
+        ).await
+    }
+
+    async fn down(&self, manager: & sea_orm_migration::SchemaManager) ->  Result<(),sea_orm::DbErr> {
+        manager.drop_table(Table::drop().table(User::Table).to_owned()).await
+    }
+}
+```
+
+3. Add migration into migrator
+
+> TODO
+
+4. Run migrator
+
+> TODO
+
+5. Generate models
+
 > TODO
 
 ## Roadmap