Sometimes for test purposes, it is necessary to run dev server with ssl enabled. In my case, I had to test my paypal webhooks implementation and it was required by paypal to have https in url root to hook my system up with webhooks:

Here is what we can do about it:

1) Navigate terminal to your rails project location. 
2) Generate certificate-key pair bundle.  It will ask questions but it's not required to answer them. Use the following command to actually generate the pair.

openssl req -x509 -sha256 -nodes -newkey rsa:2048 -days 365 -keyout localhost.key -out localhost.crt

3) Now there are two ways to go with. 
  a) - use thin server. this was my solution. for some reason, it works better with my chrome. To install it add :

group :development do
  gem 'thin'
end

run bundle install. After it's done to run the server with our created cert and key pair use starter command:

thin start –ssl –ssl-key-file localhost.key –ssl-cert-file localhost.crt

  b) Use puma server.  With cl use: 

rails s -b 'ssl://localhost:3000?key=localhost.key&cert=localhost.crt'

In case you want to add it to rubymine:

Ok now if we start ether of servers above and access
https://localhost:3000 we will be able to run in with fake ssl cert:

If you ran puma notice that now it has line with ssl:

Ok, this all looks good, but! What if we need to access our localhost from outside of our local network? Well here is what we can do:

1) Log in to your home router and find port forwarding settings:

2) #3 - puma that is my port forwarding settings for puma server.  To make this all work we need to transfer 443(ssl) -> 3000 port. 443 is our outside port and 3000 our puma rails. 192.168.1.4 is my server IP address. Here is another more detailed screenshot:

3) Now we need to know our public IP address. Easy to check in google by asking what is my ip.
4) Accessing localhost from outside by using public ip:

Making this all work can be a bit wavy. Puma gave me a lot of trouble with ssl so I use thin in case I need to test paypal and regular puma when I need to test regular stuff. Hopefully it will save someone time.