secret_key_base set for dev and test environments

`config.secret_key_base` relied on RAILS_SECRET_TOKEN being set in
all environments. Since development and (especially) test environments
are not guaranteed to have RAILS_SECRET_TOKEN set, a check was added
for these environments to use a default value. Production will continue
to raise an error when the environment variable is unset.
Fix dciy.toml setup

Tests were all failing due to an ActiveRecord pending migration
error.
Merge pull request #22 from jwilm/fix-secure-env-token

Environment Based Security Token