add doc on moving mysql to postgres

Author: arif-ali

database/migrate-mysql-to-postgres/README.md

@@ -0,0 +1,71 @@
+# Stop Gitlab
+
+```bash
+service gitlab stop
+```
+
+# Install postgresql
+
+```bash
+sudo apt-get install -y postgresql-9.1 postgresql-client libpq-dev
+```
+
+# Initial Setup
+
+```bash
+# Login to PostgreSQL
+sudo -u postgres psql -d template1
+
+# Create a user for GitLab.
+template1=# CREATE USER git;
+
+# Create the GitLab production database & grant all privileges on database
+template1=# CREATE DATABASE gitlabhq_production OWNER git;
+
+# Quit the database session
+template1=# \q
+
+# Try connecting to the new database with the new user
+sudo -u git -H psql -d gitlabhq_production
+```
+
+# Install postgres gem
+
+```bash
+cd ~git/gitlab
+sudo -u git -H bundle install --deployment --without development test mysql aws
+```
+
+# Dump the mysql database
+
+```bash
+mysqldump --compatible=postgresql --default-character-set=utf8 -r /tmp/gitlabhq_production.mysql -u root -p gitlabhq_production
+```
+
+# Convert the mysql to postgres import
+
+```bash
+wget https://raw.github.com/lanyrd/mysql-postgresql-converter/master/db_converter.py -O /tmp/db_converter.py
+python db_converter.py /tmp/gitlab_production.mysql /tmp/gitlab_production.psql
+```
+
+# Import the database
+
+```bash
+sudo -u git -H psql -d gitlabhq_production -f /tmp/gitlab_production.psql
+```
+
+# Update database config
+
+```bash
+cd ~git/gitlab/config
+sudo -u git -H cp database.yml database.yml.backup
+sudo -u git -H cp database.yml.postgresql database.yml
+```
+
+# Start Gitlab service
+
+```bash
+service gitlab start
+service nginx restart
+```