Why does a new rails app fail to generate due to a gem install error, asking me for a password? What's the solution?

Ignoring bcrypt-3.1.10 because its extensions are not built. Try: gem pristine bcrypt --version 3.1.10

Ignoring binding_of_caller-0.7.2 because its extensions are not built. Try: gem pristine binding_of_caller --version 0.7.2

Ignoring bcrypt-3.1.10 because its extensions are not built. Try: gem pristine bcrypt --version 3.1.10

Ignoring binding_of_caller-0.7.2 because its extensions are not built. Try: gem pristine binding_of_caller --version 0.7.2

Ignoring byebug-4.0.3 because its extensions are not built. Try: gem pristine byebug --version 4.0.3

Ignoring byebug-3.5.1 because its extensions are not built. Try: gem pristine byebug --version 3.5.1

Ignoring debug_inspector-0.0.2 because its extensions are not built. Try: gem pristine debug_inspector --version 0.0.2

Ignoring json-1.8.2 because its extensions are not built. Try: gem pristine json --version 1.8.2

Ignoring json-1.8.1 because its extensions are not built. Try: gem pristine json --version 1.8.1

Ignoring mysql2-0.3.18 because its extensions are not built. Try: gem pristine mysql2 --version 0.3.18

Ignoring mysql2-0.3.17 because its extensions are not built. Try: gem pristine mysql2 --version 0.3.17

Ignoring nokogiri-1.6.6.2 because its extensions are not built. Try: gem pristine nokogiri --version 1.6.6.2

Ignoring sqlite3-1.3.10 because its extensions are not built. Try: gem pristine sqlite3 --version 1.3.10

Ignoring unf_ext-0.0.6 because its extensions are not built. Try: gem pristine unf_ext --version 0.0.6

Your user account isn't allowed to install to the system Rubygems. You can cancel this installation and run:

bundle install --path vendor/bundle

to install the gems into ./vendor/bundle/, or you can enter your password and install the bundled gems to Rubygems using sudo.

Password: