chore: remove batch_insert feature & make it default

Cargo.toml

@@ -3,12 +3,12 @@ name = "pmtree"
 version = "0.1.0"
 edition = "2021"
 
-[features]
-batch_insert = []
-
 [dev-dependencies]
 hex-literal = "0.3.4"
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
 sled = "0.34.7"
 rln = { git = "https://github.com/vacp2p/zerokit", rev = "490206a" }
-ark-serialize = "0.3.0"
+ark-serialize = "0.3.0"
+
+[dependencies]
+rayon = { version = "1.6.1", optional =  false }

README.md

@@ -16,12 +16,6 @@
 pmtree = { git = "https://github.com/Rate-Limiting-Nullifier/pmtree" }
 ```
 
-To use batch insertions you must enable `batch_insert` feature:
-```toml
-[dependencies]
-pmtree = { git = "https://github.com/Rate-Limiting-Nullifier/pmtree", features = ["batch_insert"] }
-```
-
 ## Example
 
 In-Memory DB (HashMap) + Keccak

src/tree.rs

@@ -194,9 +194,8 @@ where
     }
 
     /// Batch insertion, updates the tree in parallel.
-    /// Only available as a feature
-    #[cfg(feature = "batch_insert")]
     pub fn batch_insert(&mut self, leaves: &[H::Fr]) -> Result<()> {
+        // if leaves.len()
         Ok(())
     }