README.md in ruby-units-2.0.1 vs README.md in ruby-units-2.1.0

@@ -116,10 +116,11 @@
 Unit.new('1.5 mm').to_s("%0.2f")  # "1.50 mm".  Enter any valid format
                                     string.  Also accepts strftime format
 Unit.new('1.5 mm').to_s("in")     # converts to inches before printing
 Unit.new("2 m").to_s(:ft)         # returns 6'7"
 Unit.new("100 kg").to_s(:lbs)     # returns 220 lbs, 7 oz
+Unit.new("100 kg").to_s(:stone)   # returns 15 stone, 10 lb
 ```
 
 Time Helpers
 ------------
 
@@ -226,13 +227,25 @@
 Unit.redefine!("cup") do |cup|
   cup.display_name  = "cup"
 end
 ```
 
+### Useful methods
+
+1. `scalar` will return the numeric portion of the unit without the attached units
+2. `base_scalar` will return the scalar in base units (SI)
+3. `units` will return the name of the units (without the scalar)
+4. `base` will return the unit converted to base units (SI)
+
+### Storing in a database
+
+Units can be stored in a database as either the string representation or in two separate columns defining the scalar and the units.
+Note that if sorting by units is desired you will want to ensure that you are storing the scalars in a consistent unit (i.e, the base units).
+
 ### Namespaced Class
 
-Sometimes the default class 'Unit' may conflict with other gems or applications. Internally ruby-units defines itself using the RubyUnits namespace. The actual class of a unit is the RubyUnits::Unit. For simplicity and backwards compatiblity, the '::Unit' class is defined as an alias to '::RubyUnits::Unit'.
+Sometimes the default class 'Unit' may conflict with other gems or applications. Internally ruby-units defines itself using the RubyUnits namespace. The actual class of a unit is the RubyUnits::Unit. For simplicity and backwards compatibility, the '::Unit' class is defined as an alias to '::RubyUnits::Unit'.
 
 To load ruby-units without this alias...
 
 ```
 require 'ruby_units/namespaced'
@@ -243,5 +256,39 @@
 ```
 gem 'ruby-units', require: 'ruby_units/namespaced'
 ```
 
 Note: when using the namespaced version, the Unit.new('unit string') helper will not be defined.
+
+### Configuration
+
+Configuration options can be set like:
+
+```
+RubyUnits.configure do |config|
+  config.separator = false
+end
+```
+
+Currently there is only one configuration you can set:
+
+1. separator (true/false): should a space be used to separate the scalar from the unit part during output.
+
+
+### NOTES
+
+#### Mathn
+
+Note that the current implementation of ruby-units requires 'mathn' from the ruby standard library.
+This tends to change the behavior of integer math in ways that many people do not expect, and can be the source
+of numerous bugs and odd behaviors.  If you encounter what appears to be a bug in your code that seems to be related
+
+to the use of ruby-units, try to reproduce the bug by just including 'mathn' by itself.
+
+If you identify a bug in a gem or code that uses mathn, please file a bug report or create a pull request to fix it.
+
+#### Performance vs. Accuracy
+
+Ruby units was originally intended to provide a robust and accurate way to do arbitrary unit conversions.  
+In some cases, these conversions can result in the creation and garbage collection of a lot of intermediate objects during
+calculations.  This in turn can have a negative impact on performance.  The design of ruby-units has emphasized accuracy
+over speed.  YMMV if you are doing a lot of math involving units.