add Gitpod support

Author: bluenex

Diff for: README.md

@@ -2,6 +2,11 @@
 
 Repository for [tupleblog](http://tupleblog.github.io) (in Thai) based on [Jekyll](http://jekyllrb.com/) [HPSTR](https://github.com/mmistakes/hpstr-jekyll-theme) theme.
 
+### Write on Gitpod
+
+[Gitpod](https://gitpod.io) is an amazing online IDE especially for GitHub. You can start writing the blog on Gitpod by clicking [here](https://gitpod.io/#https://github.com/tupleblog/tupleblog.github.io) and logging in with your GitHub Authentication.
+
+
 ### `tpb` script
 
 `tpb` script is now live! `tpb.sh` will help you install and serve the site easily. All you need to have is Ruby version >= `2.5.3`.

Diff for: tpb.sh

@@ -65,8 +65,18 @@ installDeps() {
 ## debug locally
 debugLocally() {
   local config_file
+  local fwp_pid
   config_file="./_config.yml"
 
+  if type gp > /dev/null; then
+    echo -e ">> Running on Gitpod.. Forwarding port 4000 to 4001 to expose publicly..\n"
+
+    gp forward-port 4000 4001 &
+
+    # collect pid of forwarding port to kill later
+    fwp_pid="$!"
+  fi
+
   # comment url line on start
   xsed 's/^(url:.*)/\# \1/' $config_file
 
@@ -75,6 +85,12 @@ debugLocally() {
 
   # uncomment url line on stop
   xsed 's/^#\s*(url: https\:\/\/tupleblog.*)/\1/' $config_file
+
+  # if there is forward port, kill it
+  if [ ! -z "$fwp_pid" ]; then
+    echo -e "\n>> Killing pid: $fwp_pid.."
+    kill -9 "$fwp_pid"
+  fi
 }
 
 # ---------------------------