(chore) Add importing.md, instructions on using the import libraries

Author: leeky

README.md

@@ -43,3 +43,7 @@ Rebuilds the test server, runs rubocop checks, runs the test suite and cleans up
 ## API Endpoints
 
 A [full list of the API endpoints](endpoints.md) is available in a separate document.
+
+## Importing users
+
+See [this guide](importing.md) to see how to import users and suppliers.

importing.md

@@ -0,0 +1,48 @@
+# Import Users / Suppliers
+
+Users and suppliers are imported from a CSV which MUST have the following
+fields:
+
+ - personname (full name of user)
+ - email
+ - suppliername
+ - frameworkreference (the framework's RM number)
+
+Also, the file needs to encoded in UTF-8 or you'll get errors! To convert an
+existing file, run the following on the command line:
+
+`iconv -c -f "US-ASCII" -t "UTF-8" input.csv > output.csv`
+
+The following commands can be run from the Rails console, given a `csv`
+variable that contains the contents of a CSV as a string.
+
+# Importing suppliers
+
+Running `require 'supplier_import'; SupplierImport.new(csv).run!` will:
+
+ - Create any suppliers that don't already exist in the database
+ - Assign these suppliers to the correct frameworks (NB: these should already
+     exist)
+
+# Importing users
+
+First, you'll need to obtain the Auth0 client_id, token and domain. Then you'll
+need to set the `csv` variable as above.
+
+Once you have these, run the following from the Rails console.
+
+```ruby
+client = Auth0Client.new(client_id: client_id, token: token, domain: domain)
+UserImport.new(csv, client).run!
+```
+
+You'll see an output like this (one for every row in the CSV)
+
+```
+auth0:1234566788,email@example.com,password,John Smith
+```
+
+**Make a note of this, as it's the only place where you can see the passwords
+generated for each user.**
+
+