diff --git a/.env b/.env
index 31f1c32f..549b76a0 100755
--- a/.env
+++ b/.env
@@ -1,8 +1,8 @@
-export PG_DATABASE_URL=postgres://granite:password@localhost:5432/granite_db
-export MYSQL_DATABASE_URL=mysql://granite:password@localhost:3306/granite_db
-export SQLITE_DATABASE_URL=sqlite3:./granite.db
-export CURRENT_ADAPTER=pg
-export PG_VERSION=10.4
-export MYSQL_VERSION=5.7
-export SQLITE_VERSION=3110000
-export SQLITE_VERSION_YEAR=2016
+PG_DATABASE_URL=postgres://granite:password@localhost:5432/granite_db
+MYSQL_DATABASE_URL=mysql://granite:password@localhost:3306/granite_db
+SQLITE_DATABASE_URL=sqlite3:./granite.db
+CURRENT_ADAPTER=pg
+PG_VERSION=10.4
+MYSQL_VERSION=5.7
+SQLITE_VERSION=3110000
+SQLITE_VERSION_YEAR=2016
diff --git a/Dockerfile b/Dockerfile
index 92cb7889..95c64555 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,4 +1,4 @@
-FROM crystallang/crystal:0.29.0
+FROM crystallang/crystal:0.30.0
 
 ARG sqlite_version=3110000
 ARG sqlite_version_year=2016
diff --git a/README.md b/README.md
index 7ce9d9e9..9d11b999 100644
--- a/README.md
+++ b/README.md
@@ -29,11 +29,7 @@ The test suite depends on access to a PostgreSQL, MySQL, and SQLite database to
 There is a self-contained testing environment provided via the `docker-compose.yml` file in this repository.
 We are testing against multiple databases so you have to specify which docker-compose file you would like to use.
 Replace "{database_type}" with "mysql" or "pg" or "sqlite". Before you can run the docker configuration you have to set the appropriate
-env variables. To do so you can either load them yourself or load the .env file
-
-```
-$ source .env
-```
+env variables. To do so you can either load them yourself or modify the `.env` file that docker-compose loads by default.
 
 You can find postgres versions at https://hub.docker.com/_/postgres/
 You can find mysql versions at https://hub.docker.com/_/mysql/
diff --git a/docker-compose.yml b/docker-compose.yml
index 390c381d..d64b2737 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -2,7 +2,7 @@ version: '2'
 services:
   spec:
     build: .
-    command: 'bash -c "cd /app/user && bin/ameba && crystal tool format --check && crystal spec --warnings all --error-on-warnings"'
+    command: 'bash -c "cd /app/user && bin/ameba && crystal tool format --check && crystal spec --warnings all"'
     working_dir: /app/user
     environment:
       PG_DATABASE_URL: 'postgres://postgres:@pg:5432/postgres'
diff --git a/shard.yml b/shard.yml
index c66e7a79..87873bb3 100644
--- a/shard.yml
+++ b/shard.yml
@@ -13,20 +13,20 @@ license: MIT
 dependencies:
   db:
     github: crystal-lang/crystal-db
-    version: ~> 0.5.1
+    version: ~> 0.6.0
 
 development_dependencies:
   mysql:
     github: crystal-lang/crystal-mysql
-    version: ~> 0.7.0
+    version: ~> 0.8.0
 
   sqlite3:
     github: crystal-lang/crystal-sqlite3
-    version: ~> 0.12.0
+    version: ~> 0.13.0
 
   pg:
     github: will/crystal-pg
-    version: ~> 0.16.1
+    version: ~> 0.18.0
 
   ameba:
     github: veelenga/ameba
diff --git a/spec/granite/converters/uuid_spec.cr b/spec/granite/converters/uuid_spec.cr
index 752f069e..3f5ec1bd 100644
--- a/spec/granite/converters/uuid_spec.cr
+++ b/spec/granite/converters/uuid_spec.cr
@@ -25,7 +25,7 @@ describe Granite::Converters::Uuid do
     describe ".to_db" do
       it "should convert a UUID enum into Bytes" do
         uuid = UUID.random
-        Granite::Converters::Uuid(Bytes).to_db(uuid).should eq uuid.to_slice
+        Granite::Converters::Uuid(Bytes).to_db(uuid).should eq uuid.bytes.to_slice
       end
     end
 
@@ -34,7 +34,7 @@ describe Granite::Converters::Uuid do
         uuid = UUID.new "cfe37f98-fdbf-43a3-b3d8-9c3288fb9ba6"
 
         rs = FieldEmitter.new.tap do |e|
-          e._set_values([uuid.to_slice])
+          e._set_values([uuid.bytes.to_slice])
         end
 
         Granite::Converters::Uuid(Bytes).from_rs(rs).should eq uuid
diff --git a/spec/granite/query/spec_helper.cr b/spec/granite/query/spec_helper.cr
index fd55a566..d0f4e3a4 100644
--- a/spec/granite/query/spec_helper.cr
+++ b/spec/granite/query/spec_helper.cr
@@ -22,11 +22,11 @@ end
 
 def builder
   {% if env("CURRENT_ADAPTER").id == "pg" %}
-  Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Pg
+    Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Pg
   {% elsif env("CURRENT_ADAPTER").id == "mysql" %}
-  Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Mysql
+    Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Mysql
   {% else %}
-  Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Sqlite
+    Granite::Query::Builder(Model).new Granite::Query::Builder::DbType::Sqlite
   {% end %}
 end
 
diff --git a/spec/mocks/db_mock.cr b/spec/mocks/db_mock.cr
index 64d20f02..8425648a 100644
--- a/spec/mocks/db_mock.cr
+++ b/spec/mocks/db_mock.cr
@@ -3,7 +3,7 @@ class FakeStatement < DB::Statement
     FieldEmitter.new
   end
 
-  protected def perform_exec(args : Enumerable)
+  protected def perform_exec(args : Enumerable) : DB::ExecResult
     DB::ExecResult.new 0_i64, 0_i64
   end
 end
@@ -11,11 +11,11 @@ end
 class FakeContext
   include DB::ConnectionContext
 
-  def uri
+  def uri : URI
     URI.new ""
   end
 
-  def prepared_statements?
+  def prepared_statements? : Bool
     false
   end
 
@@ -30,11 +30,11 @@ class FakeConnection < DB::Connection
     @prepared_statements = false
   end
 
-  def build_unprepared_statement(query : String)
+  def build_unprepared_statement(query : String) : FakeStatement
     FakeStatement.new self
   end
 
-  def build_prepared_statement(query : String)
+  def build_prepared_statement(query : String) : FakeStatement
     FakeStatement.new self
   end
 end
@@ -65,9 +65,10 @@ class FieldEmitter < DB::ResultSet
     end
   end
 
-  def move_next
+  def move_next : Bool
     @position += 1
     @field_position = 0
+    @position < @values.size
   end
 
   def read
@@ -80,11 +81,11 @@ class FieldEmitter < DB::ResultSet
     end
   end
 
-  def column_count
+  def column_count : Int32
     @values.size
   end
 
-  def column_name(index : Int32)
+  def column_name(index : Int32) : String
     "Column #{index}"
   end
 end
diff --git a/src/adapter/mysql.cr b/src/adapter/mysql.cr
index 23479958..f9a44989 100644
--- a/src/adapter/mysql.cr
+++ b/src/adapter/mysql.cr
@@ -30,7 +30,7 @@ class Granite::Adapter::Mysql < Granite::Adapter::Base
     log statement, elapsed_time
   end
 
-  def insert(table_name : String, fields, params, lastval)
+  def insert(table_name : String, fields, params, lastval) : Int64
     statement = String.build do |stmt|
       stmt << "INSERT INTO #{quote(table_name)} ("
       stmt << fields.map { |name| "#{quote(name)}" }.join(", ")
diff --git a/src/adapter/pg.cr b/src/adapter/pg.cr
index 4d20853f..9b4f5fab 100644
--- a/src/adapter/pg.cr
+++ b/src/adapter/pg.cr
@@ -39,7 +39,7 @@ class Granite::Adapter::Pg < Granite::Adapter::Base
     log statement, elapsed_time
   end
 
-  def insert(table_name : String, fields, params, lastval)
+  def insert(table_name : String, fields, params, lastval) : Int64
     statement = String.build do |stmt|
       stmt << "INSERT INTO #{quote(table_name)} ("
       stmt << fields.map { |name| "#{quote(name)}" }.join(", ")
diff --git a/src/adapter/sqlite.cr b/src/adapter/sqlite.cr
index 226d1d4d..3292c190 100644
--- a/src/adapter/sqlite.cr
+++ b/src/adapter/sqlite.cr
@@ -31,7 +31,7 @@ class Granite::Adapter::Sqlite < Granite::Adapter::Base
     log statement, elapsed_time
   end
 
-  def insert(table_name : String, fields, params, lastval)
+  def insert(table_name : String, fields, params, lastval) : Int64
     statement = String.build do |stmt|
       stmt << "INSERT INTO #{quote(table_name)} ("
       stmt << fields.map { |name| "#{quote(name)}" }.join(", ")
diff --git a/src/granite/converters.cr b/src/granite/converters.cr
index 77b52b9b..bd4d102b 100644
--- a/src/granite/converters.cr
+++ b/src/granite/converters.cr
@@ -10,7 +10,9 @@ module Granite::Converters
       {% if T == String %}
         value.to_s
       {% elsif T == Bytes %}
-        value.to_slice.dup
+        # we need a heap allocated slice
+        v = value.bytes.each.to_a
+        Slice.new(v.to_unsafe, v.size)
       {% else %}
         {% raise "#{@type.name}#to_db does not support #{T} yet." %}
       {% end %}