add migrate-data.md file detailing data migration for #81

migrate-data.md

@@ -0,0 +1,49 @@
+# Migrate Hit Data from Filesystem to PostgreSQL
+
+The Node.js MVP saves data to the filesystem
+because that was the _simplest_ way
+of storing data without having to manage a database.
+See: [hits-nodejs/lib/db_filesystem.js#L26-L68](https://github.com/dwyl/hits-nodejs/blob/d896b0c1aae5f99054be67726c6186b4ff662cd3/lib/db_filesystem.js#L26-L68)
+https://github.com/dwyl/hits/issues/81
+
++ [x] Log-in to the Linode instance and inspect how many directories have been created
+  (_this is the number of people - GitHub usernames - using the hits badge_)
+
+```sh
+ssh [email protected]
+```
+
++ [x] Count the number of log files in the `/logs` directory:
+```sh
+ls | wc -l
+787
+```
+
++ [x] zip the data on Linode instance to get it off the instance -
+because I will be running the Elixir script on my `localhost`.
+https://unix.stackexchange.com/questions/93139/zip-an-entire-folder-using-gzip
+
+```sh
+cd hits
+tar -zcvf data.tar.gz logs/
+```
+
++ [x] download the data archive to `localhost`
+
+https://stackoverflow.com/questions/9427553/how-to-download-a-file-from-server-using-ssh
+
+```sh
+scp [email protected]:hits/logs.tar.gz ./logs.tar.gz
+```
+
++ [x] unzip data on `localhost`
+
+```sh
+tar -zxvf logs.tar.gz
+```
+
++ [ ] write the script
+  + [ ] insert data into `hits_dev` PostgreSQL on `localhost`
++ [ ] run the script
++ [ ] export the data from `hits_dev` PostgreSQL on `localhost`
++ [ ] load the data on the remote server