Add new package with methods to save and load compressor state (#63)

auto_compressor/src/lib.rs

@@ -0,0 +1,9 @@
+//! This is a tool that uses the synapse_compress_state library to
+//! reduce the size of the synapse state_groups_state table in a postgres
+//! database.
+//!
+//! It adds the tables state_compressor_state and state_compressor_progress
+//! to the database and uses these to enable it to incrementally work
+//! on space reductions
+
+pub mod state_saving;