Updates for relative URLs (#752)

Added a couple notes in the start doc to refer to the docker example, updated text for the messages too.

deploy/dockerfiles/subpath.example.yml

@@ -1,4 +1,4 @@
-# this file distributed as an example of serving LS under proxy with subpath http://localhost/foo/ without any warranties. If you need to adjust it to your deployment scenario, manually modify subdomain.example.simple.conf nginx config, Label Studio env vars and postgres DB settings
+# this file is distributed as an example of serving Label Studio under proxy with subpath http://localhost/foo/ without any warranties. If you need to adjust it to your deployment scenario, manually modify the subdomain.example.simple.conf nginx config, Label Studio env vars and postgres DB settings
 version: '3.3'
 
 services:

docs/source/guide/start.md

@@ -87,6 +87,10 @@ nginx:
 ...
 ```
 
+## Run Label Studio on Docker with a host and subdomain
+
+To run Label Studio on Docker with a host and subdomain, you can refer to the example `deploy/dockerfiles/subpath.example.yml` Docker YAML file. To customize it for your environment, manually modify the `nginx/subdomain.example.simple.conf` NGINX configuration file, the relevant Label Studio environment variables, and the PostgreSQL database settings for your environment. 
+
 ## Run Label Studio with HTTPS
 To run Label Studio with HTTPS and access the web server using HTTPS in the browser, specify a certificate and private key when starting Label Studio. 
 

setup.py

@@ -10,8 +10,8 @@
     print('~========================================================~')
     print('| Your python version is %i.%i and Label Studio has a      |' % (sys.version_info[0], sys.version_info[1]))
     print('| lot of installation problems with this Python version. |')
-    print('| Please, switch to Python 3.6 - 3.8 to avoid problems   |')
-    print('| with installation.                                     |')
+    print('| Please use Python 3.6 - 3.8 to avoid problems with     |')
+    print('| your installation.                                     |')
     print('~========================================================~')
     print()