Escapes strings when doing env add

It escapes the value to be saved and searches only
for full key names using grep -w

https://github.com/platanus/negroku/commit/321e27257619316585db8004c4375b6171ac5d3f
fix(gemspec): Updates the summary and description
chore(cli): Update gli version
chore(cli): Adds inquirer.rb as a dependency
feat(cli): Adds main cli module
feat(cli): Adds main negroku command