As part of SilverBullet’s Vim support, the VIMRC page allows you to run a set of ex commands on boot. To use this functionality, create a page in your space named VIMRC and put a fenced code block (as demonstrated below) with one ex command per line, for example:

imap jj <Esc>

To manually reload your VIMRC you can use the Editor: Vim: Load VIMRC command.