import migrations and don't require diesel_cli for admins (#555)

* import migrations via macro

* panic on database not to the latest migration

* add subcommand to plm

* create migration that run tantivy index creation

* remove diesel_cli from places it was

* use our migration system for tests

* create table __diesel_schema_migrations if needed

migrations/sqlite/2019-04-28-201506_create_tantivy_index/down.sql

@@ -0,0 +1,6 @@
+-- This file should undo anything in `up.sql`
+--#!|_conn, path: &Path| {
+--#!    let mut pb = path.to_path_buf();
+--#!    pb.push("search_index");
+--#!    std::fs::remove_dir_all(pb).map_err(Error::from)
+--#!}

migrations/sqlite/2019-04-28-201506_create_tantivy_index/up.sql

@@ -0,0 +1,10 @@
+-- Your SQL goes here
+--#!|conn: &Connection, path: &Path| {
+--#!    let mut pb = path.to_path_buf();
+--#!    pb.push("search_index");
+--#!	let searcher = super::search::Searcher::create(&pb)?;
+--#!	searcher.fill(conn)?;
+--#!	searcher.commit();
+--#!	Ok(())
+--#!}
+