Implement channel permissions.

src/database/mutual.rs

@@ -0,0 +1,35 @@
+use super::get_collection;
+
+use bson::{bson, doc};
+use mongodb::options::FindOneOptions;
+
+/*pub struct MutualGuild {
+
+}
+
+pub fn find_mutual_guilds(user_id: String, target_id: String) -> Vec<> {
+
+}*/
+
+pub fn has_mutual_connection(user_id: String, target_id: String) -> bool {
+    let col = get_collection("guilds");
+    if let Ok(result) = col.find_one(
+        doc! {
+            "$and": [
+                { "members": { "$elemMatch": { "id": user_id   } } },
+                { "members": { "$elemMatch": { "id": target_id } } },
+            ]
+        },
+        FindOneOptions::builder()
+            .projection(doc! { "_id": 1 })
+            .build(),
+    ) {
+        if result.is_some() {
+            true
+        } else {
+            false
+        }
+    } else {
+        false
+    }
+}