Update acsengine.md
Fix typo
@@ -93,7 +93,7 @@ make bootstrap
make build
```
-The build process leaves the compiled `acs-engine` binary in the `bin` directory. Make sure everything completed successfully bu running `bin/acs-engine` without any arguments:
+The build process leaves the compiled `acs-engine` binary in the `bin` directory. Make sure everything completed successfully by running `bin/acs-engine` without any arguments:
```
# ./bin/acs-engine
