Migrate architecture.md to Hugo

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Author: dscho

architecture.html

@@ -1,3 +1,6 @@
+---
+title: The architecture of GitGitGadget
+---
 # How does GitGitGadget process user comments on PRs?
 
 GitGitGadget is implemented as a GitHub App (with the very imaginative name ["GitGitGadget"](https://github.com/apps/gitgitgadget)), which means that a webhook is called on certain events, such as new PR comments on PRs (e.g. `issue_comment`).
@@ -148,4 +151,4 @@ The two pipelines are identical except for these aspects:
 
 ### Git GUI's branches
 
-As GitGitGadget can also be used to contribute Git GUI patches and patch series, there is also the [Synchronize git-gui.git (branches only) to GitGitGadget](https://dev.azure.com/gitgitgadget/git/_build?definitionId=10) pipeline. It mirrors the branches of Pratyush Yadav's repository (i.e. the current Git GUI maintainer's authoritative repository) into the `git-gui/*` namespace on `gitgitgadget/git`.
+As GitGitGadget can also be used to contribute Git GUI patches and patch series, there is also the [Synchronize git-gui.git (branches only) to GitGitGadget](https://dev.azure.com/gitgitgadget/git/_build?definitionId=10) pipeline. It mirrors the branches of Pratyush Yadav's repository (i.e. the current Git GUI maintainer's authoritative repository) into the `git-gui/*` namespace on `gitgitgadget/git`.