**Why**: To be able to support Rails 5 without deprecation warnings,
we need to replace `before_filter` with `before_action`.
`before_action` is not supported in Rails 3.2, so we need to bump the
major version number since this will be a breaking change for people
who can't upgrade Rails.
**Why**:
The `encryptor` gem, which is used for the new OTP encryption feature,
requires Ruby 2.0 or later.
Also, Rails 5.0 requires Ruby 2.2.2 or greater, so we need to ignore
1.9.3, 2.0, and 2.1 when running RAILS_VERSION=master on Travis.
**Why**:
I noticed that recent builds started failing on Travis for no apparent reason. I then saw that Travis was using a different version of bundler compared to builds from 2 months ago. This version of bundler seems to be incompatible with certain versions of Ruby.
By making sure bundler is up to date, it allows Travis to install the gems on all the versions of Ruby that this repo supports.
Andrés Riveros
Ryan McGeary
Moncef Belyamani
Sam Clegg
Paul Bowsher
Dmitrii Golub
Ross Kaffenberger