Update USAGE

Author: northeastprince

lib/generators/solid_queue/install/USAGE

@@ -5,7 +5,7 @@ Example:
     bin/rails generate solid_queue:install
 
     This will perform the following:
-        Adds solid_queue db schema
+        Adds solid_queue db migration
         Adds default configurations
         Replaces Active Job's adapter in environment configuration
         Installs bin/jobs binstub to start the supervisor