Add .md extension to Markdown documents

This will cause them to be rendered on GitLab and other git hosts'
web interfaces.

3 files changed, 4 insertions, 4 deletions

diff --git a/ARCH b/ARCH.md
index 5f7ce7b..77218f1 100644
--- a/ARCH
+++ b/ARCH.md
@@ -6,7 +6,7 @@ Introduction
 
 This is an architecture document for Lorry Controller. It is aimed at
 those who develop the software, or develop against its HTTP API. See
-the file `README` for general information about Lorry Controller.
+the file `README.md` for general information about Lorry Controller.
 
 
 Requirements
diff --git a/INSTALL b/INSTALL.md
index 5344093..d7ad241 100644
--- a/INSTALL
+++ b/INSTALL.md
@@ -233,7 +233,7 @@ the Downstream Host must be given permission to read, but not write,
 to it.  Only administrators of Lorry Controller should be permitted
 to push to it.
 
-The configuration files stored in CONFGIT are documented in README.
+The configuration files stored in CONFGIT are documented in `README.md`.
 
 ## Installing Lorry and Lorry Controller
 
diff --git a/README b/README.md
index f2afb80..32c804d 100644
--- a/README
+++ b/README.md
@@ -20,12 +20,12 @@ recovering from any problems. LC has a web based administration
 interface, and an HTTP API for reporting and controlling its state.
 
 This README file documents the LC configuration file and general use.
-For the architecture of LC and the HTTP API, see the `ARCH` file.
+For the architecture of LC and the HTTP API, see the `ARCH.md` file.
 
 Installation
 ------------
 
-See the INSTALL file.
+See the `INSTALL.md` file.
 
 Lorry Controller configuration: overview
 ------------------------------