This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
Many security scanners like to inject NULL in inputs causing application
to exception out and return a 500
We now handle this exception and render a 400 status back
This updates tests to use latest rails 5 practice
and updates ALL dependencies that could be updated
Performance testing shows that performance has not regressed
if anything it is marginally faster now.
Sam Saffron
Joffrey JAFFEUX
Vinoth Kannan
Guo Xiang Tan
OsamaSayegh