feat: add doc/openvpn.md

doc/openvpn.md

@@ -7,6 +7,5 @@ sudo apt update
 
 * install
 ```
-sudo apt update
 sudo apt install openvpn --no-install-recommends
 ```

doc/osmconvert.md

@@ -0,0 +1,11 @@
+# Setup osmconvert
+
+* update Apt repository cache
+```
+sudo apt update
+```
+
+* install
+```
+sudo apt install osmctools --no-install-recommends
+```