Add tokio dependency

Cargo.lock

@@ -1209,6 +1209,7 @@ dependencies = [
  "serde",
  "sqlx",
  "structopt",
+ "tokio 1.5.0",
  "toml",
  "warp 0.3.1",
 ]
@@ -2086,6 +2087,18 @@ dependencies = [
  "mio 0.7.11",
  "num_cpus",
  "pin-project-lite 0.2.6",
+ "tokio-macros",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c49e3df43841dafb86046472506755d8501c5615673955f6aa17181125d13c37"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]

Cargo.toml

@@ -16,6 +16,7 @@ warp = { version = "^0.3", default-features = false, features = ["compression",
 structopt = { version = "^0.3", features = ["wrap_help"] }
 toml = "^0.5"
 serde = { version = "^1.0", features = ["derive"] }
+tokio = { version = "^1.0", features = ["rt-multi-thread", "macros", ] }
 
 [features]
 default = ["sqlite"]