prserve insertion order of react/role mappings

Cargo.toml

@@ -16,3 +16,4 @@ serde_yaml = "^0.8"
 serenity = "0.8.0"
 simplelog = "^0.7.4"
 guard = "0.5.0"
+indexmap = "1.3.1"

src/config.rs

+extern crate indexmap;
 use serde::Deserialize;
 use serde_yaml;
 use serenity::model::id;
-use std::collections::HashMap;
+use indexmap::IndexMap;
 use std::fs;
 
 lazy_static! {
@@ -44,8 +45,10 @@ impl UccbotConfig {
     }
 }
 
+pub type ReactRoleMap = IndexMap<String, id::RoleId>;
+
 #[derive(Debug, Deserialize, Clone)]
 pub struct ReactionMapping {
     pub message: serenity::model::id::MessageId,
-    pub mapping: HashMap<String, id::RoleId>,
+    pub mapping: ReactRoleMap,
 }

src/reaction_roles.rs

-use crate::config::CONFIG;
+use crate::config::{CONFIG, ReactRoleMap};
 use crate::util::{get_react_from_string, get_string_from_react};
 use serenity::{
     client::Context,
@@ -178,7 +178,7 @@ fn get_all_role_reaction_message(
     ctx: &Context,
 ) -> Vec<(
     Message,
-    &'static HashMap<String, serenity::model::id::RoleId>,
+    &'static ReactRoleMap,
 )> {
     let guild = ctx.http.get_guild(CONFIG.server_id).unwrap();
     info!("  Find role-react message: guild determined");