diff --git a/.gitignore b/.gitignore
index e6350fc..a749442 100644
--- a/.gitignore
+++ b/.gitignore
@@ -130,3 +130,5 @@ Cargo.lock
 **/*.rs.bk
 
 # End of https://www.gitignore.io/api/rust,macos,jetbrains+all
+
+.env
diff --git a/Cargo.toml b/Cargo.toml
index acb3b10..aecc25e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -6,14 +6,22 @@ edition = "2018"
 categories = ["database"]
 
 [dependencies]
+dotenv = "0.13.0"
 serde_json = "1.0.39"
 
-[dependencies.postgres]
+[dependencies.pg]
 version="0.15.2"
 features=["with-serde_json"]
 optional=true
+package="postgres"
 
-[dependencies.rusqlite]
+[dependencies.slite]
 version="0.17.0"
 features=["chrono","serde_json","url"]
-optional=true
\ No newline at end of file
+optional=true
+package="rusqlite"
+
+[features]
+default=['postgres']
+postgres=['pg']
+sqlite=['slite']
\ No newline at end of file
diff --git a/src/drivers.rs b/src/drivers.rs
deleted file mode 100644
index d03e369..0000000
--- a/src/drivers.rs
+++ /dev/null
@@ -1,20 +0,0 @@
-pub trait DatabaseDriver {
-    fn query(&self, query: &str) -> Result<(), ()>;
-}
-
-pub struct Postgres;
-pub struct SQLite;
-
-
-impl DatabaseDriver for Postgres {
-    fn query(&self, _query: &str) -> Result<(), ()> {
-        Ok(())
-    }
-}
-
-impl DatabaseDriver for SQLite {
-    fn query(&self, _query: &str) -> Result<(), ()> {
-        Ok(())
-    }
-}
-
diff --git a/src/drivers/mod.rs b/src/drivers/mod.rs
new file mode 100644
index 0000000..d0f6e62
--- /dev/null
+++ b/src/drivers/mod.rs
@@ -0,0 +1,26 @@
+//! Drivers
+//!
+//! Drivers represent a connection to a specific type of database engine
+use std::fmt;
+
+#[cfg(feature="pg")]
+mod postgres;
+
+#[cfg(feature="sqlite")]
+mod sqlite;
+
+
+#[derive(Debug)]
+struct Connection;
+
+#[derive(Debug)]
+struct QueryResult;
+
+
+/// Database Driver Trait
+///
+/// Interface between the database connection library and the query builder
+pub trait DatabaseDriver: fmt::Debug {
+    /// Runs a basic sql query on the database
+    fn query(&self, query: &str) -> Result<(), ()>;
+}
diff --git a/src/drivers/postgres.rs b/src/drivers/postgres.rs
new file mode 100644
index 0000000..be7473b
--- /dev/null
+++ b/src/drivers/postgres.rs
@@ -0,0 +1,13 @@
+use super::*;
+
+use pg;
+
+#[derive(Debug)]
+pub struct Postgres;
+
+#[cfg(feature="pg")]
+impl DatabaseDriver for Postgres {
+    fn query(&self, _query: &str) -> Result<(), ()> {
+        Ok(())
+    }
+}
\ No newline at end of file
diff --git a/src/drivers/sqlite.rs b/src/drivers/sqlite.rs
new file mode 100644
index 0000000..1ef71ca
--- /dev/null
+++ b/src/drivers/sqlite.rs
@@ -0,0 +1,7 @@
+pub struct SQLite;
+
+impl DatabaseDriver for SQLite {
+    fn query(&self, _query: &str) -> Result<(), ()> {
+        Ok(())
+    }
+}
\ No newline at end of file
diff --git a/src/lib.rs b/src/lib.rs
index 987e0c6..3c34dff 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,6 +1,9 @@
-/// # StringQB
-///
-/// A query builder using mostly strings, with methods following common SQL syntax
+//! # StringQB
+//!
+//! A query builder using mostly strings, with methods following common SQL syntax
+#![warn(missing_docs)]
+
+pub mod drivers;
+pub mod query_builder;
+pub mod types;
 
-mod drivers;
-mod query_builder;
diff --git a/src/query_builder.rs b/src/query_builder.rs
index 508db1c..d4c1aa0 100644
--- a/src/query_builder.rs
+++ b/src/query_builder.rs
@@ -1,4 +1,7 @@
-use std::any::Any;
+//! QueryBuilder
+//!
+//! The QueryBuilder creates sql queries from chained methods
+use std::any::{Any, TypeId};
 use std::collections::HashMap;
 
 use crate::drivers::DatabaseDriver;
@@ -39,10 +42,10 @@ struct QueryState {
     group_array: HashMap<String, String>,
 
     // Values to apply to prepared statements
-    pub values: Vec<String>,
+    pub values: Vec<Box<dyn Any>>,
 
     // Values to apply to where clauses in prepared statements
-    pub where_values: Vec<String>,
+    pub where_values: Vec<Box<dyn Any>>,
 
     limit: u32,
 
@@ -61,13 +64,15 @@ impl QueryState {
     }
 }
 
+/// The struct representing a query builder
 #[derive(Default, Debug)]
 pub struct QueryBuilder {
     state: QueryState,
-    driver: Option<DatabaseDriver>,
+    driver: Option<Box<dyn DatabaseDriver>>,
 }
 
 impl QueryBuilder {
+    /// Creates a new QueryBuilder instance
     pub fn new() -> QueryBuilder {
         QueryBuilder {
             state: QueryState::new(),
@@ -75,7 +80,8 @@ impl QueryBuilder {
         }
     }
 
-    pub fn set(mut self, key: String, value: String) -> Self {
+    /// Set a key and value for an insert or update query
+    pub fn set(mut self, key: String, value: Box<dyn Any>) -> Self {
         self.state.set_array_keys.push(key);
         self.state.values.push(value);
 
@@ -90,8 +96,8 @@ mod tests {
     #[test]
     fn set_key_value() {
         let builder = QueryBuilder::new();
-        let builder = builder.set("foo".to_string(), "bar".to_string());
+        let builder = builder.set("foo".to_string(), Box::new("bar".to_string()));
 
-        assert_eq!(builder.state.values, vec!["bar"]);
+        assert!(builder.state.values[0].is::<String>());
     }
 }
\ No newline at end of file
diff --git a/src/types.rs b/src/types.rs
new file mode 100644
index 0000000..17266d6
--- /dev/null
+++ b/src/types.rs
@@ -0,0 +1 @@
+//! Shared Types for different Database drivers