Rails => adding, removing index and foreign key => Order

                                                  Go through this order

• Add index 
• Add foreign key

Then in down method do opposite i.e.

• Remove foreign key
• Remove index

Enabling mouse scroll in TMUX

                                                                   One of the problems i encountered while using tmux is the mouse scroll ain't working few months ago and i never tried to google how to fix that. Today after getting quite frustated i finally googled and found out this simple solution to enable mouse scroll in tmux ... Just press Ctrl + b and then press : (colon). After this a small orange color bar pops up in the bottom and there you have to write the following command "setw -g mode-mouse on" without quotes.
That's it!