Follow web role logs when no roles are specified

lib/mrsk/cli/app.rb

@@ -143,13 +143,12 @@ class Mrsk::Cli::App < Mrsk::Cli::Base
       run_locally do
         info "Following logs on #{MRSK.primary_host}..."
 
-        roles = MRSK.roles_on(MRSK.primary_host)
+        MRSK.specific_roles ||= ["web"]
+        role = MRSK.roles_on(MRSK.primary_host).first
 
-        roles.each do |role|
         info MRSK.app(role: role).follow_logs(host: MRSK.primary_host, grep: grep)
         exec MRSK.app(role: role).follow_logs(host: MRSK.primary_host, grep: grep)
       end
-      end
     else
       since = options[:since]
       lines = options[:lines].presence || ((since || grep) ? nil : 100) # Default to 100 lines if since or grep isn't set