Deploy lessonnote to heroku with migrations

lessonnote-deploy.sh

[check if `heroku` is installed]

# Note, that for production, you're going to need to find+replace lessonnote-staging to lessonnote-production
heroku maintenance:on --app lessonnote-staging

# Nato:  The output of 
# git tags
# will look like this:
#
# 1.0
# 1.1
# 1.2
# 2.0
# 2.2

oldver = [NATO!]
newver = [NATO!]

#Now we need to push the git repository to heroku.

#but it's probably safer to check if the remote exists, first.

# Nato:  The output of
# git remote
# will look like this:
#
# lessonnote-production
# lessonnote-staging
# master
#
# You just need to check if lessonnote-staging exists in that list
# If it doesn't fail the script and give some useful error message

#After that we do the actual push.  You will want the porcelain output, so it should look like this:

git push -f --porcelain lessonnote-staging $newver^{}:master
#Note that the real syntax, without variables, is git push -f --porcelain lessonnote-staging v2.2^{}:master

# Check the output of the above command.  The last line should be "Done".  No quotes.
# Otherwise it might be nice to output the last 10 lines or something


#Now we want to run the migrations

heroku run rake db:migrate --app lessonnote-staging

#You're going to want to run the output of that and check for
#
# rake aborted!
#
# If you see that, follow the error path.

# IF NO RAKE ERROR
  #All is well, let's turn maintenance mode off
	heroku maintenance:off --app lessonnote-staging
	# Output something nice.  Like some ASCII art of a rainbow pooping flowers.
	# Or just a message letting us know it worked.


# ELSE IF RAKE ERROR
	# Now we need to roll back the code, and turn off maintenance mode

	git push -f --porcelain lessonnote-staging $oldver^{}:master

	#Check that again that it ended with 
	# Done

	#If it didn't give a hard error and explain that the deployment failed, but you were unable to rollback.
	#The server is still in maintenance mode, and will need to be manually rectified

	#Otherwise...

	heroku maintenance:off --app lessonnote-staging

	#Now output something about the deployment failing and being rolled back to the previous version.
	#If you're super nice, you would output some of the error from that db:migrate command.