Clarify setting ENV

[amandabee]

@knowtheory

At the top of the azure.rb we need to clarify setting the ENV variable -- if you set it in a virtualenv will that stick? Are you assuming a virtualenv? Or will that AZURE_KEY be available globally?

[knowtheory]

Yep! The Azure and GCP scripts both read some data off the commandline, i'd like to make the Azure script run the way the GCP one does (you pass a file in as an ENV variable) and then it does the right thing. But haven't gotten there yet, it's on the todo list:

• make reading credential files from the commandline work
• make the script explain what to do with credential files.

[knowtheory]

Okay, the script now takes credentials if they are required. So for example you do this:

ruby ./lib/ocr.rb google google_cloud_vision/credentials.json documents/*

likewise the Azure instructions are:

ruby ./lib/ocr.rb azure azure/credentials.json documents/*

[amandabee]

It sounds like we need a "how to use this repo" section in the README.md for the whole repo. So, see #9

[amandabee]

Closing b/c the instructions have moved past this.