Implemented leaving a gamenight on the server/database side

gamenight-database/src/gamenight_participants.rs

@@ -1,4 +1,4 @@
-use diesel::{ExpressionMethods, Insertable, QueryDsl, Queryable, RunQueryDsl};
+use diesel::{BoolExpressionMethods, ExpressionMethods, Insertable, QueryDsl, Queryable, RunQueryDsl};
 use serde::{Serialize, Deserialize};
 use uuid::Uuid;
 
@@ -25,4 +25,10 @@ pub fn get_participants(conn: &mut DbConnection, id: &Uuid) -> Result<Vec<Uuid>,
 
 pub fn insert_gamenight_participant(conn: &mut DbConnection, gp: GamenightParticipant) -> Result<usize, DatabaseError> {
     Ok(gp.insert_into(gamenight_participant::table).execute(conn)?)
+}
+
+pub fn delete_gamenight_participant(conn: &mut DbConnection, gp: GamenightParticipant) -> Result<usize, DatabaseError> {
+    Ok(gamenight_participant::table
+        .filter(gamenight_participant::gamenight_id.eq(&gp.gamenight_id).and(gamenight_participant::user_id.eq(gp.user_id)))
+        .execute(conn)?)
 }