Add an option to limit max concurrent downloads

Signed-off-by: lzzy12 <jhashivam2020@gmail.com>

README.md

@@ -2,7 +2,7 @@
 This is a telegram bot writen in python for mirroring files on the internet to our beloved Google Drive.
 
 ## Inspiration 
-This project is heavily inspired from @out396 's telegram bot which is written in JS.
+This project is heavily inspired from @out386 's telegram bot which is written in JS.
 
 ## Features supported:
 - Mirroring direct download links to google drive
@@ -70,3 +70,5 @@ Fill up rest of the fields. Meaning of each fields are discussed below:
 ```
 python3 -m bot
 ```
+
+###### You can limit maximum concurrent downloads by changing the value of MAX_CONCURRENT_DOWNLOADS in aria.sh. By default, it's set to 2

aria.sh

@@ -1,5 +1,7 @@
 export MAX_DOWNLOAD_SPEED=0
+export MAX_CONCURRENT_DOWNLOADS=2
 aria2c --enable-rpc --rpc-listen-all=false --rpc-listen-port 6800 \
   --max-connection-per-server=10 --rpc-max-request-size=1024M \
   --seed-time=0.01 --min-split-size=10M --follow-torrent=mem --split=10 \
-   --daemon=true --allow-overwrite=true --max-overall-download-limit=$MAX_DOWNLOAD_SPEED --max-overall-upload-limit=1K
+   --daemon=true --allow-overwrite=true --max-overall-download-limit=$MAX_DOWNLOAD_SPEED \
+   --max-overall-upload-limit=1K --max-concurrent-downloads=$MAX_CONCURRENT_DOWNLOADS