An error occurred while installing mimemagic (0.3.10), and Bundler cannot continue.
Make sure thatgem install mimemagic -v ‘0.3.10’ –source ‘https://rubygems.org/’` succeeds before bundling.`

Going back, it says something like this
Fetching mimemagic 0.3.10
Installing mimemagic 0.3.10 with native extensions
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

Install shared-mime-info

brew install shared-mime-info

bundle install

bundle install

mimemagic has been updated and the error is gone.