unmanagedBase <<= baseDirectory { base => base / "libs" }
unmanagedBase <<= baseDirectory { base => base / "libs" }
Manually managing dependencies involves copying any jars that you want to use to the lib
directory. sbt will put these jars on the classpath during compilation, testing, running, and when using the interpreter. You are responsible for adding, removing, updating, and otherwise managing the jars in this directory. No modifications to your project definition are required to use this method unless you would like to change the location of the directory you store the jars in.
If your project requires a dependency that is not present in a repository, a direct URL to its jar can be specified as follows:
libraryDependencies += "slinky" % "slinky" % "2.1" from "http://slinky2.googlecode.com/svn/artifacts/2.1/slinky.jar"
The URL is only used as a fallback if the dependency cannot be found through the configured repositories. Also, the explicit URL is not included in published metadata (that is, the pom or ivy.xml).