Adding alias to rake db:schema:load command. (#5281)

plugins/rails/rails.plugin.zsh

@@ -57,6 +57,7 @@ alias rdrs='rake db:reset'
 alias rdtc='rake db:test:clone'
 alias rdtp='rake db:test:prepare'
 alias rdmtc='rake db:migrate db:test:clone'
+alias rdsl='rake db:schema:load'
 alias rlc='rake log:clear'
 alias rn='rake notes'
 alias rr='rake routes'