Translation support + french.

backend/src/data/db/user.rs

@@ -7,6 +7,7 @@ use crate::{
     consts,
     data::model,
     hash::{hash, verify_password},
+    services::user,
 };
 
 #[derive(Debug)]
@@ -162,6 +163,16 @@ WHERE [id] = $1
         })
     }
 
+    pub async fn set_user_lang(&self, user_id: i64, lang: &str) -> Result<()> {
+        sqlx::query("UPDATE [User] SET [lang] = $2 WHERE [id] = $1")
+            .bind(user_id)
+            .bind(lang)
+            .execute(&self.pool)
+            .await
+            .map(|_| ())
+            .map_err(DBError::from)
+    }
+
     pub async fn sign_up(&self, email: &str, password: &str) -> Result<SignUpResult> {
         self.sign_up_with_given_time(email, password, Utc::now())
             .await