feat: add docs to main (#1559)

docs/developer/develop/tutorial/note/backend.md

@@ -0,0 +1,71 @@
+# Develop Backend Program
+
+## Clone Code
+
+  Open the IDE of backend Dev Container, open Terminal, clone your code to the `/Code` directory
+
+  ```sh
+  gh auth login
+
+  cd /Code
+  git clone https://github.com/beclab/terminus-app-demo.git
+  ```
+  
+  You can then open the backend code in the IDE for development.
+  
+  ![server IDE](/images/developer/develop/tutorial/backend/dev.jpg)
+
+## Connect Database
+
+  In the Dev Container, you can access database details through environment variables. You can do this by adding the database parameters into the container using environment variables when you deploy it.
+
+  Take `gorm` as an example:
+  ```go
+  import (
+    "fmt"
+    "os"
+    "strconv"
+
+    "gorm.io/driver/postgres"
+    "gorm.io/gorm"
+  )
+
+
+  func init() {
+    var err error
+
+    db_host = os.Getenv("DB_HOST")
+    db_port, err = strconv.Atoi(os.Getenv("DB_PORT"))
+    if err != nil {
+        panic(err)
+    }
+    db_username = os.Getenv("DB_USER")
+    db_password = os.Getenv("DB_PWD")
+    db_name = os.Getenv("DB_NAME")
+  }
+
+
+  func main(){
+    dsn := fmt.Sprintf("host=%s user=%s password=%s dbname=%s port=%d sslmode=disable TimeZone=Asia/Shanghai",
+  	db_host, db_username, db_password, db_name, db_port)
+    db, err := gorm.Open(postgres.Open(dsn), &gorm.Config{})
+    if err != nil {
+  	  panic(err)
+    }
+
+  }
+  ```
+
+## Debug
+
+  After completing the development, you can run and debug your code in the IDE.
+
+  ![run and debug](/images/developer/develop/tutorial/backend/debug.jpg)
+
+  You can also run your code in the Terminal, for example:
+  
+  ```sh
+  go run main.go
+  ```
+  
+  Now, you can debug your interface with your front-end program.