feat(blog): add post about managing multiple vterm instances in Emacs

- Add post-7.md covering buffer renaming technique for multiple vterm sessions
- Include practical use cases and step-by-step guide
- Target Emacs users who want to improve terminal workflow efficiency

src/blog/post-7.md

@@ -0,0 +1,50 @@
+---
+title: 'How to Open Multiple vterm Instances in Emacs Using Buffer Renaming'
+pubDate: 2026-01-18
+author: 'Nakahara Daisuke'
+tags: ["Emacs", "vterm"]
+---
+
+## Introduction
+
+If you're using [vterm](https://github.com/akermu/emacs-libvterm) in Emacs, you've probably encountered situations where you need multiple terminal instances running simultaneously.
+
+This article shows you how to leverage buffer renaming to open multiple vterm instances in Emacs.
+
+## The Problem: Can You Only Open One vterm?
+
+By default, when you run `M-x vterm` to start a vterm session and then execute `M-x vterm` again, it simply switches to the existing vterm buffer instead of opening a new terminal.
+
+This behavior leads many users to believe that "you can only run one vterm instance at a time."
+
+## The Solution: Rename Your Buffers
+
+The trick is simple: **by renaming the existing vterm buffer, you can create additional vterm instances**.
+
+### Step-by-Step Guide
+
+1. Launch your first vterm with `M-x vterm`
+2. Execute `C-x x r` or `M-x rename-buffer`
+3. Enter a new buffer name (e.g., `*vterm-dev*`, `*vterm-git*`, etc.)
+4. Run `M-x vterm` again to open a new vterm instance
+
+Repeat these steps as many times as needed to create multiple vterm buffers.
+
+## Real-World Use Cases
+
+Here's how I use this workflow in my daily development:
+
+- **vterm-copilot**: Interactive development with GitHub Copilot CLI
+- **vterm-main**: General command execution and file operations
+
+By managing multiple vterm instances, you can complete all your work without ever leaving Emacs.
+
+## Conclusion
+
+With the rise of AI-powered CLI tools, terminal-based workflows are becoming increasingly important. For Emacs users, mastering vterm is more valuable than ever.
+
+I hope this article helps you boost your development productivity in Emacs!
+
+---
+
+> **Note**: The review and translation were assisted by an AI generative model. The author is responsible for the final content.