In this lightning talk at the Red Dot Ruby Conference 2015, Christopher Rigor discusses the transformative impact of Docker on the deployment of Rails applications. Traditionally, Rails deployments utilize Capistrano to manage the release process, which involves manually editing server settings via SSH, managing directories, and restarting servers. Rigor outlines the conventional deployment workflow and identifies the limitations associated with using VMs and Capistrano for Rails applications.

Key Points Discussed:
- Current Deployment Practices: Rigor describes the traditional method of deploying Rails applications using Capistrano, highlighting the hassle of managing SSH access and directories.
- Advantages of Docker: He explains how Docker simplifies the deployment process by encapsulating everything needed to run an application within a container, such as the specific Ruby version required.
- Container Advantages: Rigor suggests that running multiple containers on a VM allows for better resource utilization. Each container can run different applications simultaneously without conflicting.
- Docker Deployments: Instead of creating new directories for each release, Docker enables deploying the application in distinct containers, allowing load balancers to easily switch between them, improving efficiency and reducing downtime.
- Building Docker Images: Rigor demonstrates how to use a Dockerfile to create a Docker image by specifying a base image and including necessary commands, which streamlines the setup process for Rails applications.
- Supportive Tools: He discusses the ecosystem surrounding Docker, including Docker Hub for image storage and Docker Compose for managing multiple containers, making it easier to handle applications at scale.
- Challenges with Docker: Despite its advantages, Rigor points out challenges like logging and file system management that come with using Docker.
- Introduction to Day's Platform: He briefly introduces a platform called Days that supports Docker and offers a Heroku-like deployment mechanism using Git, which automates container management.

In conclusion, Christopher emphasizes the potential of Docker to enhance Rails deployments while acknowledging the challenges that come with this transition. The talk serves as an introduction for developers considering Docker as a solution for deploying Rails applications, highlighting both the triumphs and pitfalls of moving away from traditional deployment strategies.