Implemented owner-only command .cacheusers to force users into the database, closes #425

src/NadekoBot/data/strings/commands/commands.en-US.yml

@@ -2363,3 +2363,8 @@ doas:
   desc: "Execute the command as if you were the target user. Requires bot ownership and server administrator permission."
   args:
     - "@Thief .give all @Admin"
+cacheusers:
+  desc: Caches users of a Discord server and saves them to the database.
+  args:
+    - ""
+    - "serverId"

src/NadekoBot/data/strings/responses/responses.en-US.json

@@ -1058,5 +1058,7 @@
   "sticker_missing_name": "Please specify a name for the sticker.",
   "thread_deleted": "Thread Deleted",
   "thread_created": "Thread Created",
-  "supported_languages": "Supported Languages"
+  "supported_languages": "Supported Languages",
+  "cache_users_pending": "Updating users, please wait...",
+  "cache_users_done": "{0} users were added and {1} users were updated."
 }