Rename database tables to use plural names

src/schema.rs

@@ -1,7 +1,7 @@
 // @generated automatically by Diesel CLI.
 
 diesel::table! {
-    chat (id) {
+    chats (id) {
         id -> Integer,
         telegram_id -> BigInt,
         calendar -> Text,
@@ -14,16 +14,16 @@ diesel::table! {
 }
 
 diesel::table! {
-    reminder (id) {
+    reminders (id) {
         id -> Integer,
         chat_id -> Integer,
         days_ahead -> BigInt,
     }
 }
 
-diesel::joinable!(reminder -> chat (chat_id));
+diesel::joinable!(reminders -> chats (chat_id));
 
 diesel::allow_tables_to_appear_in_same_query!(
-    chat,
-    reminder,
+    chats,
+    reminders,
 );