Update README.md

fix install burrow in readme

Signed-off-by: Casey Kuhlman <casey@monax.io>

README.md

@@ -36,7 +36,7 @@ make build
 
 This will build the `burrow` and `burrow-client` binaries and put them in the `bin/` directory. They can be executed from there or put wherever is convenient.
 
-You can also install `burrow` into `$GOPATH/bin` with `make install_db`,
+You can also install `burrow` into `$GOPATH/bin` with `make install_burrow`,
 
 ## Usage