Update README.md

README.md

@@ -25,7 +25,56 @@ Or install it yourself as:
 
 ## Usage
 
-TODO: Write usage instructions here
+Before you can use fog-aws, you must require it in your application:
+
+```ruby
+require 'fog/aws'
+```
+
+Since it's a bad practice to have your credentials in source code, you should load them from default fog configuration file: ```~/.fog```. This file could look like this:
+
+```
+default:
+  aws_access_key_id:     AKIAKFA8FKVJBJS8W3JG
+  aws_secret_access_key: k5OVuSAkh4dGeEiKHRC2ke0fSpX/5qOKGaoV+HBm
+```
+
+### Connecting to EC2 service
+```ruby
+ec2 = Fog::Compute.new :provider => 'AWS', :region => 'us-west-2'
+```
+
+You can review all the requests available with this service using ```#requests``` method:
+
+```ruby
+ec2.requests # => [:allocate_address, :assign_private_ip_addresses, :associate_address, ...]
+```
+
+### Launch an EC2 on-demand instance:
+
+```ruby
+response = ec2.run_instances(
+  "ami-23ebb513",
+  1,
+  1,
+  "InstanceType"  => "t1.micro",
+  "SecurityGroup" => "ssh",
+  "KeyName"       => "miguel"
+)
+instance_id = response.body["instancesSet"].first["instanceId"] # => "i-02db5af4"
+instance = ec2.servers.get(instance_id)
+instance.wait_for { ready? }
+puts instance.public_ip_address # => "54.200.201.120"
+```
+
+### Terminate an EC2 instance:
+
+```ruby
+instance = ec2.servers.get("i-02db5af4")
+instance.destroy
+```
+
+Fog::AWS is more than EC2 since it supports many services provided by AWS. The best way to learn and to know about how many services are supported is to take a look at the source code. To review the tests directory and to play with the library in ```irb``` can be very helpful resources as well.
 
 ## Contributing