[Alexey?]

RewriteCond %{HTTP_HOST} ^adminfuel.com [nc] 
RewriteRule ^(.*)$ http://www.adminfuel.com/$1 [r=301,nc]

or

RewriteCond %{HTTP_HOST} ^adminfuel.com  
RewriteRule ^(.*)$ http://www.adminfuel.com/$1 [r=301,nc]

and

Options +FollowSymLinks 
RewriteEngine on
RewriteCond %{HTTP_HOST} .
RewriteCond %{HTTP_HOST} !^example\.com
RewriteRule (.*) http://example.com/$1 [R=301,L]

and

Options +FollowSymLinks 
RewriteEngine on 
RewriteCond %{HTTP_HOST} ^yoursite.com [NC] 
RewriteRule ^(.*)$ http://www.yoursite.com/$1 [L,R=301]